cli: specify common options in a new group

Actions on modems from specific interfaces, like 3GPP, will also need the modem
to be specified.

The new 'Common' option group will handle all options to specify objects.

cli/mmcli-modem.c

@@ -43,7 +43,6 @@ typedef struct {
 static Context *ctx;
 
 /* Options */
-static gchar *modem_str;
 static gboolean info_flag; /* set when no action found */
 static gboolean monitor_state_flag;
 static gboolean enable_flag;
@@ -55,10 +54,6 @@ static gchar *create_bearer_str;
 static gchar *delete_bearer_str;
 
 static GOptionEntry entries[] = {
-    { "modem", 'm', 0, G_OPTION_ARG_STRING, &modem_str,
-      "Specify modem by path or index. Shows modem information if no action specified.",
-      NULL
-    },
     { "monitor-state", 'w', 0, G_OPTION_ARG_NONE, &monitor_state_flag,
       "Monitor state of a given modem",
       NULL
@@ -124,7 +119,7 @@ mmcli_modem_options_enabled (void)
                  !!delete_bearer_str +
                  !!factory_reset_str);
 
-    if (n_actions == 0 && modem_str) {
+    if (n_actions == 0 && mmcli_get_common_modem_string ()) {
         /* default to info */
         info_flag = TRUE;
         n_actions++;
@@ -759,7 +754,7 @@ mmcli_modem_run_asynchronous (GDBusConnection *connection,
 
     /* Get proper modem */
     mmcli_get_modem  (connection,
-                      modem_str,
+                      mmcli_get_common_modem_string (),
                       cancellable,
                       (GAsyncReadyCallback)get_modem_ready,
                       NULL);
@@ -775,7 +770,9 @@ mmcli_modem_run_synchronous (GDBusConnection *connection)
 
     /* Initialize context */
     ctx = g_new0 (Context, 1);
-    ctx->object = mmcli_get_modem_sync (connection, modem_str, &ctx->manager);
+    ctx->object = mmcli_get_modem_sync (connection,
+                                        mmcli_get_common_modem_string (),
+                                        &ctx->manager);
     ctx->modem = mm_object_get_modem (ctx->object);
 
     /* Request to get info from modem? */