SUNRPC: Fix "EPIPE" error on mount of rpcsec_gss-protected partitions

 gss_create_upcall() should not error just because rpc.gssd closed the
 pipe on its end. Instead, it should requeue the pending requests and then
 retry.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index c76ea22..16a2458 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -174,7 +174,7 @@
 		goto out;
 	msg = (struct rpc_pipe_msg *)filp->private_data;
 	if (msg != NULL) {
-		msg->errno = -EPIPE;
+		msg->errno = -EAGAIN;
 		list_del_init(&msg->list);
 		rpci->ops->destroy_msg(msg);
 	}
@@ -183,7 +183,7 @@
 	if (filp->f_mode & FMODE_READ)
 		rpci->nreaders --;
 	if (!rpci->nreaders)
-		__rpc_purge_upcall(inode, -EPIPE);
+		__rpc_purge_upcall(inode, -EAGAIN);
 	if (rpci->ops->release_pipe)
 		rpci->ops->release_pipe(inode);
 out: