Revert "fix: skip tests for mongo engine on python v2.6"

This reverts commit 2e107edc.

flask_admin/tests/mongoengine/test_basic.py

@@ -5,10 +5,6 @@ from nose.plugins.skip import SkipTest
 from flask_admin._compat import PY2, as_unicode
 if not PY2:
     raise SkipTest('MongoEngine is not Python 3 compatible')
-# Skip test on Python 2.6 since it is still supported by flask-admin:
-import sys
-if sys.version_info[0] == 2 and sys.version_info[1] == 6:
-    raise SkipTest('MongoEngine is not Python 2.6 compatible as of its 0.11 version.')
 
 from wtforms import fields, validators