gui: Set CConnman byte counters earlier to avoid uninitialized reads
gui: Set CConnman byte counters earlier to avoid uninitialized reads

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

Former-commit-id: 386db38e14b144b0713f0378e1409a9838afa611
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin