[GFS2] Speed up lock_dlm's locking (move sprintf)

The following patch speeds up lock_dlm's locking by moving the sprintf
out from the lock acquisition path and into the lock creation path. This
reduces the amount of CPU time used in acquiring locks by a fair amount.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Acked-by: David Teigland <teigland@redhat.com>