Fix the timestamp wrong answer conversion bug before epoch time
Add one more test case for timestamp before epoch
Merge branch 'master' of github.com:VoltDB/voltdb into ENG-6161-timestamp-before-epoch
clean up the timestamp conversion function and add more test cases
Use my old to get the correct sql timestamp before epoch
Merge pull request #1331 from VoltDB/ENG-6161-timestamp-before-epoch

Eng 6161 timestamp before epoch