nfs: Remove unused variable from write.c

When CONFIG_NFS=y and CONFIG_NFS_V3_{,V4}=n we get the following warning.

	fs/nfs/write.c: In function ‘nfs_writeback_done’:
	fs/nfs/write.c:1246:21: warning: unused variable ‘server’

 Remove the variable 'server' to fix the above warning.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/write.c

@@ -1243,7 +1243,6 @@ void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
 {
 	struct nfs_writeargs	*argp = &data->args;
 	struct nfs_writeres	*resp = &data->res;
-	struct nfs_server	*server = NFS_SERVER(data->inode);
 	int status;
 
 	dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
@@ -1277,7 +1276,7 @@ void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
 		if (time_before(complain, jiffies)) {
 			dprintk("NFS:       faulty NFS server %s:"
 				" (committed = %d) != (stable = %d)\n",
-				server->nfs_client->cl_hostname,
+				NFS_SERVER(data->inode)->nfs_client->cl_hostname,
 				resp->verf->committed, argp->stable);
 			complain = jiffies + 300 * HZ;
 		}