Fixes Bug 1074245 - make pg crashstore do it's own truncation 

the processor has always truncated processed crash values to fit the columns in
PG's 'reports' table.  That has meant that all storage systems have had their
fields limited by the definition of that PG table.  

Beginning with the Processor2015, the processor will no longer truncate the
fields for the convenience of PG.  That means that PG must to it's own field
truncation.  

Modifiy the PG crashstorage class to enforce field lengths for its own columns,
without changing the processed crash for everyone else.