[sepia] teuthology VM upgraded to Bionic

Hello all, The teuthology VM has been upgraded to Ubuntu Bionic. Additionally, the teuthology worker processes are using the latest master which means python3. If you run teuthology commands from the teuthology VM, you will likely need to rebootstrap. `cd` to wherever your teuthology checkout is, git checkout master git pull rm -rf virtualenv ./bootstrap And you should be good. Please feel free to ping or e-mail me if you need help with anything and thanks for your patience! -- David Galloway Systems Administrator, RDU Ceph Engineering IRC: dgalloway