iotest 157 pretends not to care about the image format used, but in fact
it does due to the format name not being filtered in its output. This
patch adds filtering and changes the reference output accordingly.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20160711132246.3152-1-mreitz@redhat.com
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>