Don't do remote checks on NULL files

Calling _gtk_file_consider_as_remote() with a NULL argument
results in warnings being thrown.

Note that query->priv->location being NULL is a state that does
not seem to be invalid by itself.

This could happen if you do search-as-you-type in a filechooser,
which has a filter that does not match anything *and* the current
"place" selected is "Recent".

https://bugzilla.gnome.org/show_bug.cgi?id=761552

gtk/gtkfilechooserwidget.c

@@ -7340,7 +7340,8 @@ search_start_query (GtkFileChooserWidget *impl,
 
   _gtk_search_engine_start (priv->search_engine);
 
-  if (_gtk_file_consider_as_remote (gtk_query_get_location (priv->search_query)))
+  if (gtk_query_get_location (priv->search_query) &&
+      _gtk_file_consider_as_remote (gtk_query_get_location (priv->search_query)))
     gtk_widget_show (priv->remote_warning_bar);
 }
 

gtk/gtksearchenginesimple.c

@@ -92,7 +92,8 @@ static void
 queue_if_local (SearchThreadData *data,
                 GFile            *file)
 {
-  if (!_gtk_file_consider_as_remote (file) &&
+  if (file &&
+      !_gtk_file_consider_as_remote (file) &&
       !g_file_has_uri_scheme (file, "recent"))
     g_queue_push_tail (data->directories, g_object_ref (file));
 }