nfsd4: allow setting grace period time

Allow explicit configuration of the grace period time as well as the
lease period time.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 4471046..6edfe23 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -45,7 +45,7 @@
 
 /* Globals */
 time_t nfsd4_lease = 90;     /* default lease time */
-static time_t nfsd4_grace = 90;
+time_t nfsd4_grace = 90;
 static time_t boot_time;
 static u32 current_ownerid = 1;
 static u32 current_fileid = 1;