WelcomeScreen: Don't hit an assert on some machines.

Import by module name instead of path everywhere.

Change-Id: Ibf4d4d403338bb23b44516c05114001de1d031a1
Reviewed-on: http://codereview.qt.nokia.com/1011


Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>