Remove get_object_hash.

Convert all instances of get_object_hash to use an appropriate reference
to the hash member of the oid member of struct object.  This provides no
functional change, as it is essentially a macro substitution.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
diff --git a/archive.c b/archive.c
index af23001..0687afa 100644
--- a/archive.c
+++ b/archive.c
@@ -241,7 +241,7 @@
 			len--;
 		if (args->verbose)
 			fprintf(stderr, "%.*s\n", (int)len, args->base);
-		err = write_entry(args, get_object_hash(args->tree->object), args->base,
+		err = write_entry(args, args->tree->object.oid.hash, args->base,
 				  len, 040777);
 		if (err)
 			return err;
@@ -374,7 +374,7 @@
 
 	commit = lookup_commit_reference_gently(oid.hash, 1);
 	if (commit) {
-		commit_sha1 = get_object_hash(commit->object);
+		commit_sha1 = commit->object.oid.hash;
 		archive_time = commit->date;
 	} else {
 		commit_sha1 = NULL;
@@ -390,7 +390,7 @@
 		unsigned int mode;
 		int err;
 
-		err = get_tree_entry(get_object_hash(tree->object), prefix,
+		err = get_tree_entry(tree->object.oid.hash, prefix,
 				     tree_oid.hash, &mode);
 		if (err || !S_ISDIR(mode))
 			die("current working directory is untracked");