iotests: Fix test 156

On one hand, the _make_test_img invocation for creating the target image
was missing a -u because its backing file is not supposed to exist at
that point.

On the other hand, nobody noticed probably because the backing file is
created later on and _cleanup failed to remove it: The quotation marks
were misplaced so bash tried to delete a file literally called
"$TEST_IMG{,.target}..." instead of performing brace expansion. Thus, the
files stayed around after the first run and qemu-img create did not
complain about a missing backing file on any run but the first.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
1 file changed