fix read beyond eol on missing expansion terminator

now we uniformly increment the read pointer only if we encountered a
terminator (which also implies that we were not at non-eol yet).

Task-number: QTCREATORBUG-5022
Change-Id: If4a4e7aec7423684297393fa10e50a69773b2048
Reviewed-on: http://codereview.qt.nokia.com/222


Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>