(PDB-3234) Explicitly install python 2 on debs
(PDB-3234) Explicitly install python 2 on debs

It looks like Ubuntu 16.10 may no longer have "python" available by
default, so make sure it's explicitly installed on Debian derivatives in
the pre-suite.

mullr/puppetdb,waynr/puppetdb,puppetlabs/puppetdb,mullr/puppetdb,senior/puppetdb,puppetlabs/puppetdb,senior/puppetdb,waynr/puppetdb,rbrw/puppetdb,mullr/puppetdb,puppetlabs/puppetdb,senior/puppetdb,rbrw/puppetdb,waynr/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,senior/puppetdb,waynr/puppetdb,rbrw/puppetdb,mullr/puppetdb,puppetlabs/puppetdb,rbrw/puppetdb,mullr/puppetdb