SUNRPC: xdr_read_pages needs to clear xdr->page_ptr.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index fddcccf..539c19f 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -773,6 +773,7 @@
 	 */
 	xdr->p = (__be32 *)((char *)iov->iov_base + padding);
 	xdr->end = (__be32 *)((char *)iov->iov_base + end);
+	xdr->page_ptr = NULL;
 }
 EXPORT_SYMBOL_GPL(xdr_read_pages);