PBX: Prevent incorrect hint parsing

Dynamic and pattern matching hints should not be checked for their last
known state until they are instantiated by subscribers.

(closes issue AFS-56)
Reported by: John Hardin
Patch AFS-56-pbx.diff submitted by Matt Jordan (license 6283)
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Merged revisions 414813 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 414859 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@414860 f38db490-d61c-443f-a65b-d21fe96a405b