SUNRPC: Move the bound cred to struct rpc_rqst

This will allow us to save the original generic cred in rpc_message, so
that if we migrate from one server to another, we can generate a new bound
cred without having to punt back to the NFS layer.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 257c181..08ef912 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -758,7 +758,7 @@
 				struct compound_hdr *hdr)
 {
 	__be32 *p;
-	struct rpc_auth *auth = req->rq_task->tk_msg.rpc_cred->cr_auth;
+	struct rpc_auth *auth = req->rq_cred->cr_auth;
 
 	/* initialize running count of expected bytes in reply.
 	 * NOTE: the replied tag SHOULD be the same is the one sent,