(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.
Merge pull request #789 from senior/ticket/master/pdb-247-fix-schema-warnings

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