Setup 1.1 in upgrade tests using sstableloader

This will allow us to use the python-driver more easily, while maintaining the same coverage.
Test run with changes: https://cassci.datastax.com/job/upgrade_scratch/lastCompletedBuild/testReport/
Test run without changes: https://cassci.datastax.com/job/cassandra_upgrade_dtest/lastCompletedBuild/testReport/
Document what you're doing here and why.