Remove inconsistency in CEL eventtype for user defined events.

The CEL eventtype field for ODBC and PGSQL backends should be USER_DEFINED
instead of the user defined event name supplied by the CELGenUserEvent
application.  If the field is output as a number, the user defined name
does not have a value and is always output as 21 for USER_DEFINED and the
userdeftype field would be required to supply the user defined name.

The following CEL backends (cel_odbc, cel_pgsql, cel_custom, cel_manager,
and cel_sqlite3_custom) can be independently configured to remove this
inconsistency.

* Allows cel_manager, cel_custom, and cel_sqlite3_custom to behave the
same way.

(closes issue ASTERISK-17189)
Reported by: Bryant Zimmerman

Review: https://reviewboard.asterisk.org/r/1669/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@353648 65c4cc65-6c06-0410-ace0-fbb531ad65f3