Fix double "close()" in ce_compare_data

Doing an "strace" on "git diff" shows that we close() a file descriptor
twice (getting EBADFD on the second one) when we end up in ce_compare_data
if the index does not match the checked-out stat information.

The "index_fd()" function will already have closed the fd for us, so we
should not close it again.
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

read-cache.c

@@ -61,7 +61,7 @@ static int ce_compare_data(struct cache_entry *ce, struct stat *st)
 		unsigned char sha1[20];
 		if (!index_fd(sha1, fd, st, 0, NULL))
 			match = memcmp(sha1, ce->sha1, 20);
-		close(fd);
+		/* index_fd() closed the file descriptor already */
 	}
 	return match;
 }