NFSv4: Ensure that we pass the correct dentry to nfs4_intent_set_file

This patch fixes an Oops that was reported by Gabriel Barazer.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 036d862..4b90e17 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1434,7 +1434,7 @@
 	}
 	res = d_add_unique(dentry, igrab(state->inode));
 	if (res != NULL)
-		dentry = res;
+		path.dentry = res;
 	nfs4_intent_set_file(nd, &path, state);
 	return res;
 }