MT#62181 DBRegAgent: don't wait forever

Use a timed condition waiter instead of waiting forever. This is needed
to be able to react to a requested thread shutdown.

Change-Id: I062b6045d737eb16cab8f052375d81a1988e95e8

apps/db_reg_agent/DBRegAgent.cpp

@@ -1773,7 +1773,7 @@ void DBRegAgentProcessorThread::run() {
 
   reg_agent = DBRegAgent::instance();
   while (!stop_requested()) {
-    waitForEvent();
+    waitForEventTimed(500);
     while (eventPending()) {
       rateLimitWait();
       processSingleEvent();