ENG-6462: Fix up some bad indentation
ENG-6462: Get the schema modification type setting in through the
deployment file.  Test both polarities and default.
ENG-6462: Add test verifying that changing the schema update method is
blacklisted from runtime updates.
ENG-6462: Take the coward's way out: give the AsyncCompilerAgent all
the info and let it make the decisions after it has done DDL parsing.

Write some basic tests that cover most cases.  Make tests that depend on
using adhoc DDL set the config switch properly
Merge pull request #1480 from VoltDB/eng6462

Eng6462: Add deployment switch to chose schema update mechanism (UAC or DDL)
r=wweiss