Fix NUL byte error handling on Python 3.4

Looks like Python 3.4 raises TypeError and not ValueError...

qutebrowser/config/configfiles.py

@@ -198,7 +198,7 @@ def read_config_py(filename=None):
 
     try:
         code = compile(source, filename, 'exec')
-    except ValueError as e:
+    except (ValueError, TypeError) as e:
         # source contains NUL bytes
         desc = configexc.ConfigErrorDesc("Error while compiling", e)
         raise configexc.ConfigFileErrors(basename, [desc])

tests/unit/config/test_configfiles.py

@@ -236,7 +236,7 @@ class TestConfigPy:
 
         assert len(excinfo.value.errors) == 1
         error = excinfo.value.errors[0]
-        assert isinstance(error.exception, ValueError)
+        assert isinstance(error.exception, (TypeError, ValueError))
         assert error.text == "Error while compiling"
         exception_text = 'source code string cannot contain null bytes'
         assert str(error.exception) == exception_text