sys-fs/eudev: ensure REPLACING_VERSIONS is processed as a list

sys-fs/eudev: ensure REPLACING_VERSIONS is processed as a list

REPLACING_VERSIONS is used in eudev ebuilds during pkg_postinst to determine
when udevadm control --reload should be called:
- when it is a new installation of udev
- when it is a re-emerge of the same version (or a revision-only upgrade)

REPLACING_VERSIONS *should* only ever have zero or one values, but it is
theoretically possible for it to have more than that if, for instance, a previous
upgrade failed to complete during qmerge.  If this is the case, and only one of
the multiple versions match the version of the ebuild, then we also abort as we
don't know which one is the "good" one.

Also removed duplicate code that reloads the hwdb (looks like it was a copy-paste
from sys-fs/udev)

Bug: http://bugs.gentoo.org/589530

Package-Manager: portage-2.2.28