Update the recipes to move modified initrds out

Move dracut creation out of common-post so distro-specific
changes can go in without running dracut multiple times.

Pass the right kernel version into dracut so we don't pick up
whatever `uname -r` is in koji, brew, or other build
environments.

livecd-creator copies the initrd out before post script runs, so
move it out ourselves when we're done to pick up updates.

Change-Id: I3da516d2b29c1adde28811c5b47da1199385b70e
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1152948
Signed-off-by: Ryan Barry <rbarry@redhat.com>