MDEV-7426 - federated.federated_server fails

Fixed error path of close_cached_connection_tables() to unlock mutex.

mysql-test/t/AAA.test

-SELECT 1;

sql/sql_base.cc

@@ -633,10 +633,7 @@ static my_bool close_cached_connection_tables_callback(
   /* Ignore if table is not open or does not have a connect_string */
   if (!element->share || !element->share->connect_string.length ||
       !element->ref_count)
-  {
-    mysql_mutex_unlock(&element->LOCK_table_share);
-    return FALSE;
-  }
+    goto end;
 
   /* Compare the connection string */
   if (arg->connection &&
@@ -646,20 +643,23 @@ static my_bool close_cached_connection_tables_callback(
          element->share->connect_string.str[arg->connection->length] != '\\')) ||
        strncasecmp(arg->connection->str, element->share->connect_string.str,
                    arg->connection->length)))
-    return FALSE;
+    goto end;
 
   /* close_cached_tables() only uses these elements */
   if (!(tmp= (TABLE_LIST*) alloc_root(arg->thd->mem_root, sizeof(TABLE_LIST))) ||
       !(tmp->db= strdup_root(arg->thd->mem_root, element->share->db.str)) ||
       !(tmp->table_name= strdup_root(arg->thd->mem_root,
                                      element->share->table_name.str)))
+  {
+    mysql_mutex_unlock(&element->LOCK_table_share);
     return TRUE;
+  }
 
   tmp->next_local= arg->tables;
   arg->tables= tmp;
 
+end:
   mysql_mutex_unlock(&element->LOCK_table_share);
-
   return FALSE;
 }