support all snapshottable filesystems

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Remove local copies of lxclock.h and lxccontainer.h

They should come from the lxc-dev package.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
check actual rootdev for is_lvm check

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
fix checking for lvm rootdev

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