Fix refcounting of sip_pvt in test_sip_rtpqos test and unlink it from the list of pvts.

(closes issue ASTERISK-22248)
reported by Corey Farrell
patches:
	test_sip_rtpqos.patch uploaded by Corey Farrell (license #5909)
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Merged revisions 397112 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 397133 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@397142 f38db490-d61c-443f-a65b-d21fe96a405b