debugger: codadevice: merge multiple cleanup paths

Change-Id: Ia75a833652d32e2f02ea7ed448561f619d4945cc
Reviewed-on: http://codereview.qt.nokia.com/338
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: hjk <qthjk@ovi.com>

src/plugins/debugger/gdb/codagdbadapter.cpp

@@ -1297,6 +1297,7 @@ void CodaGdbAdapter::reportRegisters()
 
 void CodaGdbAdapter::handleRegisterChildren(const CodaCommandResult &result)
 {
+    QTC_ASSERT(m_codaDevice, return);
     const QByteArray contextId = result.cookie.toByteArray();
     if (!result) {
         logMessage("Error retrieving register children of " + contextId