Cleanup indications on exit.

* Made ast_unregister_indication_country() unlink the found tone zone
before selecting a new default_tone_zone to make it impossible to select
the tone zone being unregistered again.

* Ringcadence is no longer parsed twice in store_config_tone_zone().

* Cleanup CLI commands and destroy default_tone_zone on exit.

(issue ASTERISK-20649)
Reported by: Corey Farrell
Patches:
      indications-cleanup-all.patch (license #5909) patch uploaded by Corey Farrell
      Modified
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Merged revisions 377740 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 377741 from http://svn.asterisk.org/svn/asterisk/branches/10
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Merged revisions 377742 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@377743 65c4cc65-6c06-0410-ace0-fbb531ad65f3