NFS: Split out the body of nfs4_reclaim_open_state()

Moving all of this into a new function removes the need for cramped
indentation, making the code overall easier to look at.   I also take
this chance to switch copy recovery over to using
nfs4_stateid_match_other()

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>