Remove dynamodb Py3 boto restrictions since we only test newer boto now.

tests/helpers.py

@@ -1,6 +1,5 @@
 from __future__ import unicode_literals
 import boto
-import six
 from nose.plugins.skip import SkipTest
 
 
@@ -24,19 +23,3 @@ class requires_boto_gte(object):
         if boto_version >= required:
             return test
         return skip_test
-
-
-class py3_requires_boto_gte(object):
-    """Decorator for requiring boto version greater than or equal to 'version'
-    when running on Python 3. (Not all of boto is Python 3 compatible.)"""
-    def __init__(self, version):
-        self.version = version
-
-    def __call__(self, test):
-        if not six.PY3:
-            return test
-        boto_version = version_tuple(boto.__version__)
-        required = version_tuple(self.version)
-        if boto_version >= required:
-            return test
-        return skip_test