registry: remove some unused and in their current form pointless API

Not so useful: just adds/reads stuff from an internal GList without
actually doing anything with those paths, so remove for now:

 gst_registry_add_path
 gst_registry_get_path_list

https://bugzilla.gnome.org/show_bug.cgi?id=608841

docs/gst/gstreamer-sections.txt

@@ -2314,7 +2314,6 @@ gst_registry_get
 gst_registry_get_feature_list
 gst_registry_get_feature_list_cookie
 gst_registry_get_feature_list_by_plugin
-gst_registry_get_path_list
 gst_registry_get_plugin_list
 gst_registry_add_plugin
 gst_registry_remove_plugin
@@ -2323,7 +2322,6 @@ gst_registry_feature_filter
 gst_registry_find_plugin
 gst_registry_find_feature
 gst_registry_lookup_feature
-gst_registry_add_path
 gst_registry_scan_path
 gst_registry_lookup
 gst_registry_remove_feature

gst/gstregistry.c

@@ -143,7 +143,9 @@ struct _GstRegistryPrivate
   GList *plugins;
   GList *features;
 
+#if 0
   GList *paths;
+#endif
 
   int cache_file;
 
@@ -336,6 +338,7 @@ gst_registry_get (void)
   return registry;
 }
 
+#if 0
 /**
  * gst_registry_add_path:
  * @registry: the registry to add the path to
@@ -404,7 +407,7 @@ gst_registry_get_path_list (GstRegistry * registry)
 
   return list;
 }
-
+#endif
 
 /**
  * gst_registry_add_plugin:

gst/gstregistry.h

@@ -62,8 +62,11 @@ GType                   gst_registry_get_type           (void);
 GstRegistry *           gst_registry_get                (void);
 
 gboolean                gst_registry_scan_path          (GstRegistry *registry, const gchar *path);
+
+#if 0
 void                    gst_registry_add_path           (GstRegistry * registry, const gchar * path);
 GList*                  gst_registry_get_path_list      (GstRegistry *registry);
+#endif
 
 gboolean                gst_registry_add_plugin         (GstRegistry *registry, GstPlugin *plugin);
 void                    gst_registry_remove_plugin      (GstRegistry *registry, GstPlugin *plugin);

win32/common/libgstreamer.def

@@ -931,7 +931,6 @@ EXPORTS
 	gst_query_writable_structure
 	gst_rank_get_type
 	gst_registry_add_feature
-	gst_registry_add_path
 	gst_registry_add_plugin
 	gst_registry_check_feature_version
 	gst_registry_feature_filter
@@ -943,7 +942,6 @@ EXPORTS
 	gst_registry_get_feature_list
 	gst_registry_get_feature_list_by_plugin
 	gst_registry_get_feature_list_cookie
-	gst_registry_get_path_list
 	gst_registry_get_plugin_list
 	gst_registry_get_type
 	gst_registry_lookup