For ENG-4954, initial commit with functionality, looking in tests now
For ENG-4954, add tests for blocking catalog updates
For ENG-4954, fix a misnamed ZK path
For ENG-4954, move the blocking into the transaction so it doesn't race with join
Merge pull request #754 from VoltDB/ENG-4954

ENG-4954 Don't allow catalog updates during elastic join