UC-1155
http://track.sipfoundry.org/browse/UC-1155

Modifications:
- added a catch for treating exceptions for the read/write opperations
from mongo
- there are no more core dumps for mongo errors

Saa, rls, registry and proxy don't do core dumps if mongo isn't
up and running. Registry and proxy return a 500 error and saa and
rls test the connection with the mongodb and exit with 1 in case of
failure