schemachange test app: fix for nonblocking stats--don't use table stats to check if UAC worked or not
schemachange app: only give graceful_failure back to caller
schemachange test app: address John's review comments.
Merge pull request #518 from VoltDB/pr130513-fix-schemachange-for-nonblocking-stats-notest

schemachange test app: fix for nonblocking stats--don't use table stats ...