libgis: add missing return keyword (#1751)

lib/gis/mapset_msc.c

@@ -231,7 +231,7 @@ int make_mapset_element_no_fail_on_race(const char *p_path, const char *p_elemen
  */
 int G__make_mapset_element_misc(const char *dir, const char *name)
 {
-    G_make_mapset_dir_object(dir, name);
+    return G_make_mapset_dir_object(dir, name);
 }
 
 static int check_owner(const struct stat *info)