Fix asked by Ranger.

If embedded library gets empty string as a hostname it should use embedded connection

libmysqld/libmysqld.c

@@ -145,7 +145,7 @@ mysql_real_connect(MYSQL *mysql,const char *host, const char *user,
 
   if (mysql->options.methods_to_use == MYSQL_OPT_USE_REMOTE_CONNECTION ||
       (mysql->options.methods_to_use == MYSQL_OPT_GUESS_CONNECTION &&
-       host && strcmp(host,LOCAL_HOST)))
+       host && *host && strcmp(host,LOCAL_HOST)))
     DBUG_RETURN(cli_mysql_real_connect(mysql, host, user, 
 				       passwd, db, port, 
 				       unix_socket, client_flag));