c/r: add an option to use faster inotify support in CRIU

c/r: add an option to use faster inotify support in CRIU

The idea here is that criu can use open_by_handle on a configuration which
will preserve inodes on moves across hosts, but shouldn't do that on
configurations which won't preserve inodes. Before, we forced it to always
be slow, but we don't have to do this.

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>