lxclock: move container locks into /run/lock

Previously they were $lxcpath/locks/$lxcname.  This fails if the
container is on a rofs.

The $lxcpath/$lxcname/partial file is not moved - if you can't
create it, you probably can't create the container either.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>