Since the library and almost everything got renamed to qml, we
should do so for the debugging support, too.
(CONFIG+=declarative_debug will continue to work for some time
being, but prints a deprecated warning).
Change-Id: I295155dce873e2585c1452d2bf0625ea6ce219c4
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
