object-name.h: move declarations for object-name.c functions from cache.h

Signed-off-by: Elijah Newren <newren@gmail.com>
Acked-by: Calvin Wan <calvinwan@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/rev-parse.c

@@ -15,6 +15,7 @@
 #include "refs.h"
 #include "quote.h"
 #include "builtin.h"
+#include "object-name.h"
 #include "parse-options.h"
 #include "diff.h"
 #include "revision.h"