res_pjsip_endpoint_identifier_ip: Add 'show identify(ies)' cli commands

While troubleshooting other things I realized there were no pjsip cli
commands for identify.  This patch adds them.  It also also fixes a
reference leak when a 'show endpoint' displayed identifies and properly
sets the return code if load_module can't allocate a cli formatter structure.

Tested-by: George Joseph

Review: https://reviewboard.asterisk.org/r/4212/
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Merged revisions 428725 from http://svn.asterisk.org/svn/asterisk/branches/12
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Merged revisions 428731 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@428732 65c4cc65-6c06-0410-ace0-fbb531ad65f3