For ENG-4906, switch to using concurrent hash map instead of nonblocking hash map due to unexpected memory usage
Merge branch 'master' into ENG-4906
For ENG-4906, turns out you still need to intialize the proc info map for snapshot daemon
For ENG-4906, remove redundant map population
Merge pull request #622 from VoltDB/ENG-4906

Eng 4906 Don't use NBHM because it leaks memory like a sieve