Eliminate off-server export code:
- Completely eliminate export service from client interface.
- No longer advertise data sources in messages to off-server clients
- Nobody actually cares about the returned result from EE.exportAction,
  so make it go away.
- Remove dead code.
- Get rid of the message part of ExportProtoMessage.  Make the
  AdvertisedDataSource which everyone uses a first-class object.
- We don't need bootClient() any more since it was for off-server export
  only.
For ENG-5400, First stab at making creating the index idempotent
ENG-5316 Handle Dummy catalog.
ENG-5316 javadoc update.
ENG-5338 fix. add log to dump export configuration.
ENG-5316 dont do export checking if dummy catalog.
For ENG-5400, more k-safety work to allow joining nodes to fail during the index snapshot
Use log4j for elatic context related errors in EE.
Removed unused variables from ElasticContext.cpp.
Merge branch 'master' into ENG-5316
Merge branch 'master' into ENG-5316
Merge branch 'ENG-5316' of https://github.com/VoltDB/voltdb into ENG-5316
ENG-5316 review changes.
Log previously ignored error condition at INFO to reduce panic.
Merge branch 'master' into ENG-5316
ENG-5316 make dummy isPlaceHolderCatalog
Merge pull request #911 from VoltDB/kill-offserver-export

Eliminate off-server export code
For ENG-5400, more k-safety work and some performance improvements to leader elector

For ENG-5400, fix compile error and exception handling
Merge pull request #916 from VoltDB/ENG-5316

Eng 5316
For ENG-5400, fix test bugs in leader appointer