devel/qtcreator: fix general weirdness

• there were REINPLACE_CMDs that did nothing, because the replaced strings were (no longer) in the files being edited.
• a .bak file (from REINPLACE_CMD) was left in the plist.
• testport failed in check-plist because the install target tries to strip(1) a text file (!?) and that leaves behind an empty ecp.<random> file in the dirname of the file being stripped.