sunrpc: don't use the copy variable in nested block

to clean up the code "copy" will be set prior to the block
hence it mustn't be used there.
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

net/sunrpc/xdr.c

@@ -404,8 +404,7 @@ xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
 	if (tail->iov_len != 0) {
 		if (tail->iov_len > len) {
 			char *p = (char *)tail->iov_base + len;
-			copy = tail->iov_len - len;
-			memmove(p, tail->iov_base, copy);
+			memmove(p, tail->iov_base, tail->iov_len - len);
 		}
 		/* Copy from the inlined pages into the tail */
 		copy = len;