MB-16056: Remove unsafe wildcard exception catch blocks in ExecutorThread
MB-16056: Remove unsafe wildcard exception catch blocks in ExecutorThread

ExecutorThread has two sets of catch blocks where it catches both
std::exception and wildcard (...) and simply prints a warning to the
log and continues - this is not exception *handling*.

If ExecutorThread cannot take appropriate remedial action for an
exception (which in general is impossible for a catch-all exception)
then it shouldn't catch them at all, and rely on some higher-level
handler (or more likely the C++ runtime terminating the application
due to an unhandled exception.

Therefore remove these invalid catch blocks.

Change-Id: I1472914070008a16462ba41e5cd47c9eadb3a255
Reviewed-on: http://review.couchbase.org/55487
Tested-by: buildbot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Reviewed-by: Chiyoung Seo <fcffc23db27b19ee4ebba46695ee6b50e09216a2@couchbase.com>

owendCB/ep-engine,daverigby/kv_engine,teligent-ru/ep-engine,hisundar/ep-engine,couchbase/ep-engine,daverigby/ep-engine,hisundar/ep-engine,daverigby/kv_engine,couchbase/ep-engine,hisundar/ep-engine,couchbase/ep-engine,membase/ep-engine,membase/ep-engine,teligent-ru/ep-engine,daverigby/ep-engine,owendCB/ep-engine,membase/ep-engine,daverigby/kv_engine,owendCB/ep-engine,teligent-ru/ep-engine,membase/ep-engine,couchbase/ep-engine,owendCB/ep-engine,teligent-ru/ep-engine,daverigby/ep-engine,daverigby/kv_engine,daverigby/ep-engine,hisundar/ep-engine