res/res_phoneprov: Don't cancel Asterisk load on module load failure

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Merged revisions 424985 from http://svn.asterisk.org/svn/asterisk/branches/12
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Merged revisions 424986 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@424987 65c4cc65-6c06-0410-ace0-fbb531ad65f3