o.c.alarm.beast.server: Prevent deadlock in JMS access

ServerCommunicator used to execute all JMS updates on designated work
queue and "JMS Communicator" thread.
RDB update batching changed that, some updates were performed from
"main" work queue and thread when its performs the RDB updates.

-> Deadlock possible when both write to JMS.

Reverted the ServerCommunicator.send* calls to again defer to "JMS
Communicator" thread.