app_meetme: compiler warning

Fixed a compiler warning (errors in 'dev-mode') given by gcc version 4.8.1.
The one in app_meetme involved the 'sizeof-pointer-memaccess'
(see: http://gcc.gnu.org/gcc-4.8/porting_to.html) warning. Fixed so
it would no longer issue a warning and can compile again in 'dev-mode'.

Review: https://reviewboard.asterisk.org/r/3098/
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Merged revisions 404742 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 404773 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 404781 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@404782 65c4cc65-6c06-0410-ace0-fbb531ad65f3