For ENG-3176, check for network threads when invoking ZooKeeper and crash if in the wrong thread
For ENG-3176, fix test failure
For ENG-3176, track a few more verboten threads, check if est time updating is tardy, use atomic long for tracking last message time.
ENG-4237: Accept a null deployment string in
UpdateApplicationCatalog.  Use the previous deployment settings in
this case.
ENG-4237: Allow @UpdateApplicationCatalog to pass through to the
replica without killing it.
ENG-4237: Need to preserve DR properties (invocation type, original
txn ID, unique txn ID) as the catalog work traverses through the async
compiler thread.
Merge branch 'master' into ENG-3176

Conflicts:
	src/frontend/org/voltcore/messaging/ForeignHost.java
	src/frontend/org/voltcore/messaging/HostMessenger.java
For ENG-3176, mitigate log spam from EstTime update tardiness by printing at most every 60 seconds
Merge pull request #376 from VoltDB/ENG-3176

Eng 3176
ENG-4237: Fix up/enhance a client interface check to verify that the
DR-needed info from the master is getting passed along properly.
Merge pull request #381 from VoltDB/eng4237

Eng4237
Merge branch 'master' into cow_indirection