Remove failure version number

Version numbering with this object has not currently
been useful, and we should do our best to make all changes
backwards compatible anyway so the usage of a version
number is not benefical at this time.

Change-Id: I87bcc30dd19dc9a8d3c3d7bce2174e13c4a22634

taskflow/tests/unit/test_failure.py

@@ -152,14 +152,6 @@ class FailureObjectTestCase(test.TestCase):
         }
         self.assertRaises(exceptions.InvalidFormat,
                           failure.Failure.validate, f)
-        f = {
-            'exception_str': 'blah',
-            'traceback_str': 'blah',
-            'exc_type_names': ['Exception'],
-            'version': -1,
-        }
-        self.assertRaises(exceptions.InvalidFormat,
-                          failure.Failure.validate, f)
 
     def test_valid_from_dict_to_dict(self):
         f = _captured_failure('Woot!')

taskflow/types/failure.py

@@ -121,7 +121,6 @@ class Failure(mixins.StrMixin):
     backport at https://pypi.python.org/pypi/traceback2/ to (hopefully)
     simplify the methods and contents of this object...
     """
-    DICT_VERSION = 1
 
     BASE_EXCEPTIONS = ('BaseException', 'Exception')
     """
@@ -137,10 +136,6 @@ class Failure(mixins.StrMixin):
             "cause": {
                 "type": "object",
                 'properties': {
-                    'version': {
-                        "type": "integer",
-                        "minimum": 0,
-                    },
                     'exception_str': {
                         "type": "string",
                     },
@@ -467,10 +462,6 @@ class Failure(mixins.StrMixin):
     def from_dict(cls, data):
         """Converts this from a dictionary to a object."""
         data = dict(data)
-        version = data.pop('version', None)
-        if version != cls.DICT_VERSION:
-            raise ValueError('Invalid dict version of failure object: %r'
-                             % version)
         causes = data.get('causes')
         if causes is not None:
             data['causes'] = tuple(cls.from_dict(d) for d in causes)
@@ -482,7 +473,6 @@ class Failure(mixins.StrMixin):
             'exception_str': self.exception_str,
             'traceback_str': self.traceback_str,
             'exc_type_names': list(self),
-            'version': self.DICT_VERSION,
             'causes': [f.to_dict() for f in self.causes],
         }