all: drop unused variables

Keeps build with GCC 8 happy.

mm-base-call.c:758:18: warning: variable 'response' set but not used [-Wunused-but-set-variable]
mm-base-call.c:822:18: warning: variable 'response' set but not used [-Wunused-but-set-variable]
mm-base-sms.c:908:18: warning: variable 'response' set but not used [-Wunused-but-set-variable]
mm-sms-list.c:331:25: warning: variable 'ctx' set but not used [-Wunused-but-set-variable]
mm-iface-modem-messaging.c:1210:21: warning: variable 'storage_ctx' set but not used [-Wunused-but-set-variable]
huawei/mm-plugin-huawei.c:183:18: warning: variable 'response' set but not used [-Wunused-but-set-variable]
ublox/mm-plugin-ublox.c:161:24: warning: variable 'response' set but not used [-Wunused-but-set-variable]
ublox/mm-plugin-ublox.c:159:24: warning: variable 'ctx' set but not used [-Wunused-but-set-variable]
icera/mm-modem-helpers-icera.c:218:25: warning: variable 'first_free' set but not used [-Wunused-but-set-variable]
novatel/mm-common-novatel.c:50:18: warning: variable 'response' set but not used [-Wunused-but-set-variable]

plugins/huawei/mm-plugin-huawei.c

@@ -180,12 +180,11 @@ curc_ready (MMPortSerialAt *port,
             GTask *task)
 {
     HuaweiCustomInitContext *ctx;
-    const gchar *response;
     GError *error = NULL;
 
     ctx = g_task_get_task_data (task);
 
-    response = mm_port_serial_at_command_finish (port, res, &error);
+    mm_port_serial_at_command_finish (port, res, &error);
     if (error) {
         /* Retry if we get a timeout error */
         if (g_error_matches (error,

plugins/icera/mm-modem-helpers-icera.c

@@ -215,7 +215,7 @@ mm_icera_parse_ipdpaddr_response (const gchar *response,
     GError *local = NULL;
     gboolean success = FALSE;
     char **items;
-    guint num_items, i, first_free;
+    guint num_items, i;
     gint num;
 
     g_return_val_if_fail (out_ip4_config, FALSE);
@@ -240,7 +240,7 @@ mm_icera_parse_ipdpaddr_response (const gchar *response,
 
     /* Strip any spaces on elements; inet_pton() doesn't like them */
     num_items = g_strv_length (items);
-    for (i = 0, first_free = 0; i < num_items; i++)
+    for (i = 0; i < num_items; i++)
         items[i] = g_strstrip (items[i]);
 
     if (num_items < 7) {

plugins/novatel/mm-common-novatel.c

@@ -47,10 +47,9 @@ nwdmat_ready (MMPortSerialAt *port,
               GAsyncResult *res,
               GTask* task)
 {
-    const gchar *response;
     GError *error = NULL;
 
-    response = mm_port_serial_at_command_finish (port, res, &error);
+    mm_port_serial_at_command_finish (port, res, &error);
     if (error) {
         if (g_error_matches (error,
                              MM_SERIAL_ERROR,

plugins/ublox/mm-plugin-ublox.c

@@ -156,15 +156,12 @@ quick_at_ready (MMPortSerialAt *port,
                 GAsyncResult   *res,
                 GTask          *task)
 {
-    CustomInitContext *ctx;
     MMPortProbe       *probe;
-    const gchar       *response;
     GError            *error = NULL;
 
-    ctx   = g_task_get_task_data     (task);
     probe = g_task_get_source_object (task);
 
-    response = mm_port_serial_at_command_finish (port, res, &error);
+    mm_port_serial_at_command_finish (port, res, &error);
     if (error) {
         /* On a timeout error, wait for READY URC */
         if (g_error_matches (error, MM_SERIAL_ERROR, MM_SERIAL_ERROR_RESPONSE_TIMEOUT)) {

src/mm-base-call.c

@@ -755,11 +755,10 @@ call_hangup_ready (MMBaseModem *modem,
 {
     MMBaseCall *self;
     GError *error = NULL;
-    const gchar *response;
 
     self = g_task_get_source_object (task);
 
-    response = mm_base_modem_at_command_finish (modem, res, &error);
+    mm_base_modem_at_command_finish (modem, res, &error);
     if (error) {
         if (g_error_matches (error, MM_SERIAL_ERROR, MM_SERIAL_ERROR_RESPONSE_TIMEOUT)) {
             g_task_return_error (task, error);
@@ -819,9 +818,8 @@ call_send_dtmf_ready (MMBaseModem *modem,
                       GTask *task)
 {
     GError *error = NULL;
-    const gchar *response = NULL;
 
-    response = mm_base_modem_at_command_finish (modem, res, &error);
+    mm_base_modem_at_command_finish (modem, res, &error);
     if (error) {
         mm_dbg ("Couldn't send_dtmf: '%s'", error->message);
         g_task_return_error (task, error);

src/mm-base-sms.c

@@ -905,10 +905,9 @@ store_ready (MMBaseModem *modem,
              GTask *task)
 {
     SmsStoreContext *ctx;
-    const gchar *response;
     GError *error = NULL;
 
-    response = mm_base_modem_at_command_finish (modem, res, &error);
+    mm_base_modem_at_command_finish (modem, res, &error);
     if (error) {
         g_task_return_error (task, error);
         g_object_unref (task);

src/mm-iface-modem-messaging.c

@@ -1207,10 +1207,8 @@ init_current_storages_ready (MMIfaceModemMessaging *self,
                              GTask *task)
 {
     InitializationContext *ctx;
-    StorageContext *storage_ctx;
     GError *error = NULL;
 
-    storage_ctx = get_storage_context (self);
     if (!MM_IFACE_MODEM_MESSAGING_GET_INTERFACE (self)->init_current_storages_finish (
             self,
             res,

src/mm-sms-list.c

@@ -328,11 +328,6 @@ mm_sms_list_take_part (MMSmsList *self,
                        MMSmsStorage storage,
                        GError **error)
 {
-    PartIndexAndStorage ctx;
-
-    ctx.part_index = mm_sms_part_get_index (part);
-    ctx.storage = storage;
-
     /* Ensure we don't have already taken a part with the same index */
     if (mm_sms_list_has_part (self,
                               storage,