system-settings: don't return secrets in the settings

Since only authorized users should be able to get secrets, don't return
them in the GetSettings handlers; callers need to use GetSecrets instead.

system-settings/plugins/ifcfg-rh/nm-ifcfg-connection.c

@@ -319,7 +319,10 @@ nm_ifcfg_connection_get_unmanaged (NMIfcfgConnection *self)
 static GHashTable *
 get_settings (NMExportedConnection *exported)
 {
-	return nm_connection_to_hash (nm_exported_connection_get_connection (exported));
+	NMConnection *connection = nm_exported_connection_get_connection (exported);
+
+	nm_connection_clear_secrets (connection);
+	return nm_connection_to_hash (connection);
 }
 
 static gboolean

system-settings/plugins/ifcfg-suse/nm-suse-connection.c

@@ -126,7 +126,10 @@ nm_suse_connection_new (const char *iface, NMDeviceType dev_type)
 static GHashTable *
 get_settings (NMExportedConnection *exported)
 {
-	return nm_connection_to_hash (nm_exported_connection_get_connection (exported));
+	NMConnection *connection = nm_exported_connection_get_connection (exported);
+
+	nm_connection_clear_secrets (connection);
+	return nm_connection_to_hash (connection);
 }
 
 static gboolean

system-settings/plugins/ifupdown/nm-ifupdown-connection.c

@@ -70,7 +70,10 @@ nm_ifupdown_connection_new (if_block *block)
 static GHashTable *
 get_settings (NMExportedConnection *exported)
 {
-	return nm_connection_to_hash (nm_exported_connection_get_connection (exported));
+	NMConnection *connection = nm_exported_connection_get_connection (exported);
+
+	nm_connection_clear_secrets (connection);
+	return nm_connection_to_hash (connection);
 }
 
 static gboolean

system-settings/plugins/keyfile/nm-keyfile-connection.c

@@ -67,7 +67,10 @@ nm_keyfile_connection_get_filename (NMKeyfileConnection *self)
 static GHashTable *
 get_settings (NMExportedConnection *exported)
 {
-	return nm_connection_to_hash (nm_exported_connection_get_connection (exported));
+	NMConnection *connection = nm_exported_connection_get_connection (exported);
+
+	nm_connection_clear_secrets (connection);
+	return nm_connection_to_hash (connection);
 }
 
 static GValue *