repository: clarify assignment and test order

src/repository.c

@@ -1500,12 +1500,12 @@ int git_repository_is_empty(git_repository *repo)
 	if (git_reference_lookup(&head, repo, GIT_HEAD_FILE) < 0)
 		return -1;
 
-	if (!(error = git_reference_type(head) == GIT_REF_SYMBOLIC))
+	if (!((error = git_reference_type(head)) == GIT_REF_SYMBOLIC))
 		goto cleanup;
 
-	if (!(error = strcmp(
+	if (!(error = (strcmp(
 		git_reference_symbolic_target(head),
-		GIT_REFS_HEADS_DIR "master") == 0))
+		GIT_REFS_HEADS_DIR "master") == 0)))
 			goto cleanup;
 
 	error = repo_contains_no_reference(repo);