Make debian init script conform to the LSB standard

Make debian init script conform to the LSB standard

Previously, this init script would return 1 if Asterisk was already running.
This is incorrect behavior according to the LSB standard and has been fixed by
returning 0 instead.

(closes issue ASTERISK-17958)
Reported-by: johnc
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Merged revisions 349529 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 349532 from http://svn.asterisk.org/svn/asterisk/branches/10

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@349535 65c4cc65-6c06-0410-ace0-fbb531ad65f3