Remove @entry decorator (and misc cleanup)

tests/util_test.py

@@ -1,27 +0,0 @@
-import mock
-import pytest
-import sys
-
-from pre_commit_hooks.util import entry
-
-
-@pytest.fixture
-def entry_func():
-    @entry
-    def func(argv):
-        return argv
-
-    return func
-
-
-def test_explicitly_passed_argv_are_passed(entry_func):
-    input = object()
-    ret = entry_func(input)
-    assert ret is input
-
-
-def test_no_arguments_passed_uses_argv(entry_func):
-    argv = [1, 2, 3, 4]
-    with mock.patch.object(sys, 'argv', argv):
-        ret = entry_func()
-        assert ret == argv[1:]