cleanup after browser tests; closes #2488

Makefile

@@ -21,15 +21,15 @@ mocha.js: $(SRC) browser-entry.js
 
 clean:
 	@printf "==> [Clean]\n"
-	rm -f mocha.js
+	git checkout -f -- mocha.js
 
 lint:
 	@printf "==> [Test :: Lint]\n"
 	$(ESLINT) browser-entry.js index.js karma.conf.js bin/mocha bin/_mocha "lib/**/*.js" "scripts/**/*.js" test
 
 test-node: test-bdd test-tdd test-qunit test-exports test-unit test-integration test-jsapi test-compilers test-glob test-requires test-reporters test-only test-global-only
 
-test-browser: clean mocha.js test-browser-unit test-browser-bdd test-browser-qunit test-browser-tdd test-browser-exports
+test-browser: clean mocha.js test-browser-unit test-browser-bdd test-browser-qunit test-browser-tdd test-browser-exports clean
 
 test: lint test-node test-browser