fix failing dtest for select distinct with static columns on 2.2->3.0 upgrade path

upgrade_tests/cql_tests.py:TestCQL.static_columns_with_distinct_test fails on the upgrade path from 2.2 to 3.0:

http://cassci.datastax.com/view/Upgrades/job/storage_engine_upgrade_dtest-22_tarball-30_HEAD/lastCompletedBuild/testReport/upgrade_tests.cql_tests/TestCQL/static_columns_with_distinct_test/

Once this dtest PR is merged, these tests should also run with this upgrade path on normal 3.0 jobs. Until then, you can run it with the following command:

SKIP=false CASSANDRA_VERSION=binary:2.2.0 UPGRADE_TO=git:cassandra-3.0 nosetests upgrade_tests/cql_tests.py:TestCQL.static_columns_with_distinct_test