properly decode messages from gdb

... using fromLocal8Bit instead of fromLatin1.
of course the localized messages pose a "challenge" for the various
workarounds which parse them ...

Task-number: QTCREATORBUG-504

src/plugins/debugger/gdb/trkgdbadapter.cpp

@@ -1628,7 +1628,7 @@ void TrkGdbAdapter::handleTargetRemote(const GdbResponse &record)
         emit inferiorPrepared();
     } else {
         QString msg = tr("Connecting to TRK server adapter failed:\n")
-            + _(record.data.findChild("msg").data());
+            + QString::fromLocal8Bit(record.data.findChild("msg").data());
         emit inferiorStartFailed(msg);
     }
 }