NFS: Get rid of nfs_restart_rpc()

It can trivially be replaced with rpc_restart_call_prepare.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
index c5347d2..f0268ea 100644
--- a/net/sunrpc/clnt.c
+++ b/net/sunrpc/clnt.c
@@ -850,7 +850,9 @@
 {
 	if (RPC_ASSASSINATED(task))
 		return 0;
-	task->tk_action = rpc_prepare_task;
+	task->tk_action = call_start;
+	if (task->tk_ops->rpc_call_prepare != NULL)
+		task->tk_action = rpc_prepare_task;
 	return 1;
 }
 EXPORT_SYMBOL_GPL(rpc_restart_call_prepare);