Make "Qt.declarative" available as "Qt.quick" again for Qt 4.

This was accidentally removed when switching to the new Qt modules
approach.

Change-Id: Ie8db5a183c2cc3a82d31c2793710983cf4206ef0
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
remove deprecated qbsPath preferences key

Change-Id: I8ef371816ce6a25521c70fcdfe74480ddc2cfae9
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>