Making sure that the file name field has "ant.bat" set, and
that the filtering really works.

This patch also ensures that native file separators are shown.

Task-Number: QTCREATORBUG-11628
Change-Id: Ibab8c145d0b832e5ad2e2ff62a81818e4044f13e
Reviewed-by: Daniel Teske <daniel.teske@digia.com>