Play periodic prompts for first call in a call queue

Review: https://reviewboard.asterisk.org/r/2263/
........

Merged revisions 386792 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/11@386794 f38db490-d61c-443f-a65b-d21fe96a405b