iotests: remove qemu_img_pipe_and_status()

iotests: remove qemu_img_pipe_and_status()

With the exceptional 'create' calls removed in the prior commit, change
qemu_img_log() and img_info_log() to call qemu_img() directly
instead.

For now, allow these calls to qemu-img to return non-zero on the basis
that any unusual output will be logged anyway. The very next commit
begins to enforce a successful exit code by default even for the logged
functions.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20220321201618.903471-18-jsnow@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>