src/udev/udev-event.c: restore code to allow rule generator to work

This code was dropped while importing from upstream.  It is needed
to allow the legacy renaming of interfaces like eth* or wlan*.

X-Eudev-Bug: 56
X-Eudev-Bug-URL: https://github.com/gentoo/eudev/issues/56
Signed-off-by: Anthony G. Basile <blueness@gentoo.org>