Fix some pep8 issues, mostly spaces

Before:
    4       E101 indentation contains mixed spaces and tabs
    20      E122 continuation line missing indentation or outdented
    1       E124 closing bracket does not match visual indentation
    12      E127 continuation line over-indented for visual indent
    22      E128 continuation line under-indented for visual indent
    2       E211 whitespace before '('
    12      E302 expected 2 blank lines, found 1
    1       E303 too many blank lines (3)
    4       E402 module level import not at top of file
    123     E501 line too long (81 > 79 characters)
    2       E731 do not assign a lambda expression, use a def
    3       W191 indentation contains tabs
    20      W291 trailing whitespace
    3       W293 blank line contains whitespace
    2       W391 blank line at end of file
    69      W503 line break before binary operator

After:
    20      E122 continuation line missing indentation or outdented
    12      E127 continuation line over-indented for visual indent
    22      E128 continuation line under-indented for visual indent
    123     E501 line too long (81 > 79 characters)
    2       E731 do not assign a lambda expression, use a def
    1       W291 trailing whitespace
    68      W503 line break before binary operator

tests/rules/test_dirty_untar.py

@@ -40,6 +40,7 @@ parametrize_script = pytest.mark.parametrize('script, fixed', [
     ('tar -xvf {}', 'mkdir -p foo && tar -xvf {} -C foo'),
     ('tar --extract -f {}', 'mkdir -p foo && tar --extract -f {} -C foo')])
 
+
 @parametrize_filename
 @parametrize_script
 def test_match(tar_error, filename, script, fixed):