Merge pull request #3762 from taosdata/bugfix/td-1249

[TD-1249]<fix>:memory leak in rpc

src/dnode/src/dnodeVRead.c

@@ -187,6 +187,7 @@ void dnodeSendRpcReadRsp(void *pVnode, SReadMsg *pRead, int32_t code) {
 }
 
 void dnodeDispatchNonRspMsg(void *pVnode, SReadMsg *pRead, int32_t code) {
+  rpcFreeCont(pRead->rpcMsg.pCont);
   vnodeRelease(pVnode);
   return;
 }