(PDB-247) Fixes the namespace override warnings from schema

Schema 0.2.0 has not yet been released, but has the fix for PDB-247. I
made a pre-release (0.2.0-pre-1) of the current state of the branch and
updated PuppetDB to use it.  Some PuppetDB code also needed to change as
one of the protocols is changing in 0.2.0.