Use FileManager instead of our own FileSystemWatcher, since this one only signals
the first file change (cause Qt Creator apparently removes the file and creates
a new one on each change).

Change-Id: Idacd545e41cd3ee29bfbc122526b9097039c65d0
Reviewed-on: http://codereview.qt-project.org/4975


Reviewed-by: Daniel Teske <daniel.teske@nokia.com>
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>