Make most python tests pass with Python 3.4

Dictionary order is not stable in Python < 3.6 so we need to sort
by key to have consistent results.
The LogHandler output is also different on older Python versions.
Also, don't stop running python tests after the first error.

plugins/python/regress/plugin_approval_test.py

@@ -8,7 +8,7 @@ class ApprovalTestPlugin(sudo.Plugin):
         super().__init__(plugin_options=plugin_options, **kwargs)
         self._id = "(APPROVAL {})".format(id)
         sudo.log_info("{} Constructed:".format(self._id))
-        sudo.log_info(json.dumps(self.__dict__, indent=4))
+        sudo.log_info(json.dumps(self.__dict__, indent=4, sort_keys=True))
 
     def __del__(self):
         sudo.log_info("{} Destructed successfully".format(self._id))