lxc-fedrora: New patch for systemd detection and init configuration.

Satoshi Matsumoto certainly had the right idea and in spotting a bug in
the lxc-fedora template for systemd detection.  Heart was in the right
spot but patch was not what we needed.

I've looked the patch code over for systemd support and init/upstart
support and modified the logic appropriately.  If /etc/systemd/system
exists, we'll do the right thing by systemd.  If /etc/rc.sysinit exists,
we'll do the right thing by init / upstart.  If both are installed,
we'll trying and accommodate both in case someone is playing games with
the two (I've done this).

Patch was trivial, just took more time to actually test it and create
some containers with it and verify them, than it did to code them.

Signed-off-by: Michael H. Warfield <mhw@WittsEnd.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>