Merge bitcoin-core#414: Uncomment DebugMessageHandler install

456d28a qml: uncomment DebugMessageHandler install (johnny9)

Pull request description:

  DebugMessageHandler is needed to route output to debug.log and should not have been commented out.

  Mistakenly commented out in bitcoin-core#403

ACKs for top commit:
  MarnixCroes:
    ACK 456d28a
  hebasto:
    ACK 456d28a

Tree-SHA512: c78e526deccba366854287c796e2ac4843f1aba7b936d6955b6ec2212e75fac6a4372e3994e4045a45e083c7422fb827fddb674c64a593affa1226589f14d8ab

src/qt/bitcoin.cpp

@@ -622,7 +622,7 @@ int GuiMain(int argc, char* argv[])
     qApp->installNativeEventFilter(new WinShutdownMonitor());
 #endif
     // Install qDebug() message handler to route to debug.log
-    //qInstallMessageHandler(DebugMessageHandler);
+    qInstallMessageHandler(DebugMessageHandler);
     // Allow parameter interaction before we create the options model
     app.parameterSetup();
     GUIUtil::LogQtInfo();