lockd: Remove FL_LOCKD flag

Currently lockd identifies its own locks using the FL_LOCKD flag.  This
doesn't scale well to multiple lock managers--if we did this in nfsv4 too,
for example, we'd be left with only one free flag bit.

Instead, we just check whether the file manager ops (fl_lmops) set on this
lock are our own.

The only use for this is in nlm_traverse_locks, which uses it to find locks
that need cleaning up when freeing a host or a file.

In the long run it might be nice to do reference counting instead of
traversing all the locks like this....

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/fs.h

@@ -667,7 +667,6 @@ extern spinlock_t files_lock;
 #define FL_POSIX	1
 #define FL_FLOCK	2
 #define FL_ACCESS	8	/* not trying to lock, just looking */
-#define FL_LOCKD	16	/* lock held by rpc.lockd */
 #define FL_LEASE	32	/* lease held on this file */
 #define FL_SLEEP	128	/* A blocking lock */