Merge #17906: gui: Set CConnman byte counters earlier to avoid uninitialized reads

8313fa8 gui: Set CConnman byte counters earlier to avoid uninitialized reads (Russell Yanofsky)

Pull request description:

  Initialize CConnman byte counters during construction, so GetTotalBytesRecv() and GetTotalBytesSent() methods don't return garbage before Start() is called.

  Change shouldn't have any effect outside of the GUI. It just fixes a race condition during a qt test that was observed on travis: https://travis-ci.org/bitcoin/bitcoin/jobs/634989685

ACKs for top commit:
  MarcoFalke:
    ACK 8313fa8
  promag:
    ACK 8313fa8.

Tree-SHA512: 97c246da4e28e6e0b48f685b840f96746ad75c4b157a692201c6c4702db328a88ead8507d8e1b4e608aa1882513174ec60cf3977c31b7a9d76678cc9f49b45f8

Author: fanquake

src/net.h

@@ -386,8 +386,8 @@ class CConnman
     // Network usage totals
     CCriticalSection cs_totalBytesRecv;
     CCriticalSection cs_totalBytesSent;
-    uint64_t nTotalBytesRecv GUARDED_BY(cs_totalBytesRecv);
-    uint64_t nTotalBytesSent GUARDED_BY(cs_totalBytesSent);
+    uint64_t nTotalBytesRecv GUARDED_BY(cs_totalBytesRecv) {0};
+    uint64_t nTotalBytesSent GUARDED_BY(cs_totalBytesSent) {0};
 
     // outbound limit & stats
     uint64_t nMaxOutboundTotalBytesSentInCycle GUARDED_BY(cs_totalBytesSent);