NFSv4: Kill braindead gcc warnings

nfs4_open_revalidate: 'res' may be used uninitialized
nfs4_callback_compound: ‘hdr_res.nops’ may be used uninitialized
			'op_nr’ may be used uninitialized
encode_getattr_res: ‘savep’ may be used uninitialized

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 305bea2..77a565e 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -908,7 +908,7 @@
 static struct nfs4_state *nfs4_open_delegated(struct inode *inode, int flags, struct rpc_cred *cred)
 {
 	struct nfs4_exception exception = { };
-	struct nfs4_state *res;
+	struct nfs4_state *res = ERR_PTR(-EIO);
 	int err;
 
 	do {