Make pbx_lua handle managing the autoservice better.

Make autoservice_start() and autoservice_stop() return nothing.  Also check if
the autoservice flag is set before starting or stopping the autoservice and
stop and start the autoservice when returning control to and getting control
from the pbx engine.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@317803 65c4cc65-6c06-0410-ace0-fbb531ad65f3

UPGRADE.txt

@@ -47,6 +47,7 @@ pbx_lua:
    (such as app.goto).  Now when an application such as app.goto() is called,
    control is returned back to the pbx engine and the current extension
    function stops executing.
+ - autoservice_start() and autoservice_start() no longer return a value.
 
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