Remove obsolete message

The warning that a schema already exists is obsolete as mapped tables are
now always opened instead of being reused. This causes the schema checks
to be done for each mapped table.

server/modules/routing/avrorouter/avro_schema.c

@@ -311,10 +311,6 @@ void save_avro_schema(const char *path, const char* schema, TABLE_MAP *map)
             }
         }
     }
-    else
-    {
-        MXS_NOTICE("Schema version %d already exists: %s", map->version, filepath);
-    }
 }
 
 /**