OCFS2: the o2cb statefile is created at the pool level

This avoids the obvious race if all hosts try to create it at the
same time.

Signed-off-by: David Scott <dave.scott@citrix.com>
ocfs2: describe Pool.eject

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #44 from djs55/ocfs2

More OCFS2 stuff