This sets the prefix for frameworks to "org.qt-project".
Applications keep using the default Xcode preferences
prefix.

Task-number: QTBUG-32896
Change-Id: I67384f643888f2de3dd8e36b9bce0f04ca4e16dd
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>