TST: Explicitly skip versioning tests.

The test had a check for a pandas version (0.12.0) which was out of date
with the version in requirements, meaning the tests have not been run
regularly and unstable.

Skip via the decorator to make it more noticeable that tests are not
being run.

tests/test_versioning.py

@@ -14,11 +14,10 @@
 # limitations under the License.
 
 import os
-import pandas
 import pickle
 
 from nose_parameterized import parameterized
-from unittest import TestCase
+from unittest import TestCase, skip
 
 from zipline.finance.blotter import Order
 
@@ -51,6 +50,7 @@ class VersioningTestCase(TestCase):
 
     # Only test versioning in minutely mode right now
     @parameterized.expand(object_serialization_cases(skip_daily=True))
+    @skip
     def test_object_serialization(self,
                                   _,
                                   cls,
@@ -58,14 +58,6 @@ class VersioningTestCase(TestCase):
                                   di_vars,
                                   comparison_method='dict'):
 
-        # The state generated under one version of pandas may not be
-        # compatible with another. To ensure that tests pass under the travis
-        # pandas version matrix, we only run versioning tests under the
-        # current version of pandas. This will need to be updated once we
-        # change the pandas version on prod.
-        if pandas.__version__ != '0.12.0':
-            return
-
         # Make reference object
         obj = cls(*initargs)
         for k, v in di_vars.items():