rev-parse: mark unused parameter in for_each_abbrev callback

We don't need to use the "data" parameter in this instance. Let's mark
it to avoid -Wunused-parameter warnings.

Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: peff

builtin/rev-parse.c

@@ -226,7 +226,7 @@ static int anti_reference(const char *refname, const struct object_id *oid,
 	return 0;
 }
 
-static int show_abbrev(const struct object_id *oid, void *cb_data)
+static int show_abbrev(const struct object_id *oid, void *cb_data UNUSED)
 {
 	show_rev(NORMAL, oid, NULL);
 	return 0;