As noted by theuni and Sjors in #12870, qt moc cleaning is handled by CLEAN_QT via QT_MOC_CPP in Makefile.qt.include.
In my testing I configured, built and cleaned with qt4 and qt5 both, absent the associated wildcard, and no MOC files were left after clean. Propose we revert the change and reconsider if a specific file is identified, and in that case add that file to QT_MOC_CPP.
This reverts commit 1d540046fe47eb7b6062c55ebebd801ece96231c, reversing changes made to ad960f5771dc251c8e1198dd8a82e18df4562171.