Remove cartodb from search path

All calls to the extension functions should, and are,
be properly qualified, so there is no need to keep
the cartodb schema in the search_path

scripts-available/CDB_Username.sql

@@ -7,4 +7,4 @@ $$  LANGUAGE SQL
     STABLE
     PARALLEL SAFE
     SECURITY DEFINER
-    SET search_path = @extschema@, pg_temp;
+    SET search_path = pg_temp;