The 'e' special extension fails to trigger in at least two cases.

The 'e' special extension fails to trigger in at least two cases.

The 'e' extension is a fall back for the 'i', 't', or 'T' extensions if
any of them do not exist.  Many of the places the 'e' extension was
supposed to be invoked fail because the priority was set wrong.  There
were two places where the 'e' extension was not even checked for fall
back.

* Made invoke the 'e' extension similarly to the previous 'i', 't', or 'T'
extension check and added the 'e' extension as a fall back to the two
missing locations.

* Prioritized and optimized some hangup tests associated with the 'e'
extension.

(closes issue #19136)
Reported by: kshumard
Tested by: rmudgett

Review: https://reviewboard.asterisk.org/r/1196/

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@315645 65c4cc65-6c06-0410-ace0-fbb531ad65f3