Update API versions and UPGRADE/CHANGES for 12.2.0

This patch does the following:
 * It updates the AMI version to 2.2.0 to indicate backwards compatible
   changes have been made since the last release
 * It updates the ARI version to 1.2.0 to indicate backwards compatible
   changes have been made since the last release
 * It updates the UPGRADE/CHANGES files with changes that were not
   mentioned
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Merged revisions 411529 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@411530 f38db490-d61c-443f-a65b-d21fe96a405b
process stack command even if gatekeeper client isn't register
don't destroy gatekeeper client if it is not started
don't destroy gatekeeper client in some sort of gatekeeper errors
signal rtp create condition when call cleared before rtp structure created

(closes issue ASTERISK-23460)

Reported by: Dmitry Melekhov
Patches:
	ASTERISK-23460-2.patch

Tested by: Dmitry Melekhov
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Merged revisions 411531 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 411532 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@411533 f38db490-d61c-443f-a65b-d21fe96a405b