Merge pull request #1451 from sangshuduo/fix-memory-leak-pTree

fix pTree memory leak in vnodeQueryImpl.c

src/system/detail/src/vnodeQueryImpl.c

@@ -5837,6 +5837,7 @@ int32_t doMergeMetersResultsToGroupRes(STableQuerySupportObj *pSupporter, SQuery
       } else {  // copy data to disk buffer
         if (buffer[0]->numOfElems == pQuery->pointsToRead) {
           if (flushFromResultBuf(pSupporter, pQuery, pRuntimeEnv) != TSDB_CODE_SUCCESS) {
+            tfree(pTree);
             return -1;
           }