locks: fix flock_lock_file() comment

This comment wasn't updated when lease support was added, and it makes
essentially the same mistake that the code made before a recent bugfix.

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

fs/locks.c

@@ -715,8 +715,7 @@ next_task:
 }
 
 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
- * at the head of the list, but that's secret knowledge known only to
- * flock_lock_file and posix_lock_file.
+ * after any leases, but before any posix locks.
  *
  * Note that if called with an FL_EXISTS argument, the caller may determine
  * whether or not a lock was successfully freed by testing the return