fix ahandle memory leak in tscServer.c

src/client/src/tscServer.c

@@ -400,7 +400,7 @@ void *tscProcessMsgFromServer(char *msg, void *ahandle, void *thandle) {
              pObj, pObj->signature);
     taosAddConnIntoCache(tscConnCache, pSql->thandle, pSql->ip, pSql->vnode, pObj->user);
     tscFreeSqlObj(pSql);
-    return ahandle;
+    return NULL;
   }
 
   SMeterMetaInfo *pMeterMetaInfo = tscGetMeterMetaInfo(pCmd, pCmd->clauseIndex, 0);