Fix two more possible crashes in CEL

These are locations that should return valid snapshots, but need to be
handled if not.


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@391855 f38db490-d61c-443f-a65b-d21fe96a405b
Revert parts of r391855 that were not ready to go in to trunk

git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@391856 f38db490-d61c-443f-a65b-d21fe96a405b