annotated_commit: peel to commit instead of assuming we have one

We want to allow the creation of annotated commits out of annotated tags and for
that we have to peel the reference all the way to the commit instead of stopping
at the first id it provides.

Author: carlosmn

src/annotated_commit.c

@@ -123,27 +123,27 @@ int git_annotated_commit_from_ref(
 	git_repository *repo,
 	const git_reference *ref)
 {
-	git_reference *resolved;
+	git_object *peeled;
 	int error = 0;
 
 	assert(out && repo && ref);
 
 	*out = NULL;
 
-	if ((error = git_reference_resolve(&resolved, ref)) < 0)
+	if ((error = git_reference_peel(&peeled, ref, GIT_OBJ_COMMIT)) < 0)
 		return error;
 
 	error = annotated_commit_init_from_id(out,
 		repo,
-		git_reference_target(resolved),
+		git_object_id(peeled),
 		git_reference_name(ref));
 
 	if (!error) {
 		(*out)->ref_name = git__strdup(git_reference_name(ref));
 		GITERR_CHECK_ALLOC((*out)->ref_name);
 	}
 
-	git_reference_free(resolved);
+	git_object_free(peeled);
 	return error;
 }