Reduce duplication in messages for QML Puppet checks.

Change-Id: I490c89f854465baf160bc55a65f3c3e24490a947
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
Reviewed-by: Marco Bubke <marco.bubke@digia.com>
Do not warn for combined engine if QML debugging has not been enabled

Do not bring up a message box when connecting to the QML debugging port,
but rather just log, and continue C++ debugging.

This mitigates the issue that, in some configurations, QML debugging is
enabled by default although the application might not be set up properly.

Change-Id: I29e89ada4bf14f57589c8c671452572b689cdbdb
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>