Tell between packed, unpacked and symbolic refs.

This adds a "int *flag" parameter to resolve_ref() and makes
for_each_ref() family to call callback function with an extra
"int flag" parameter.  They are used to give two bits of
information (REF_ISSYMREF and REF_ISPACKED) about the ref.

Signed-off-by: Junio C Hamano <junkio@cox.net>

server-info.c

@@ -7,7 +7,7 @@
 /* refs */
 static FILE *info_ref_fp;
 
-static int add_info_ref(const char *path, const unsigned char *sha1, void *cb_data)
+static int add_info_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 {
 	struct object *o = parse_object(sha1);