QDeclarativeDebug: Allow reconnects to QML debugger port

Allow a new client to attach once the old one was disconnected.
Done by Aurindam Jana.

Change-Id: Id85045204cc011ec6e02db2658173e652b75c07e
Reviewed-on: http://codereview.qt-project.org/5132


Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Aurindam Jana <aurindam.jana@nokia.com>