Remove all references to DeviceFormat.majorminor

And remove a bit of related code as well. Last uses of majorminor were
removed in anaconda commit d819bb940717270f4c5747e894ef0c5ac509dfe2.
majorminor was originally added in commit
2875d2009f30f52b79f6f7d15916f73b490bc635.

Signed-off-by: mulhern <amulhern@redhat.com>
Remove udev_ prefix from udev methods.

The udev namespace identifies the methods adequately.
Update method calls appropriately.

Signed-off-by: mulhern <amulhern@redhat.com>