This was added originally to keep older Qt Creator versions working.
However, any newer versions automatically set QT_QML_DEBUG too, and
checking for both actively prevented selectively enabling QtQuick1 or
QtQuick2 debuggers only.

Change-Id: I4d4a984958ef3430ebe05b267bd87185005bbe51
Reviewed-by: Aurindam Jana <aurindam.jana@digia.com>