Fix Manager Segfault When app_queue Is Unloaded

When app_queue is unloaded, some manager commands are not being unregistered
which result in a segfault.  This patch corrects this.

(closes issue ASTERISK-21397)
Reported by: Peter Katzmann, Corey Farrell
Tested by: Corey Farrell
Patches:
    asterisk-21397-missing-unreg-manager-cmd_1.8.diff
                                                 Michael L. Young (license 5026)
    asterisk-21397-missing-unreg-manager-cmd_11.diff
                                                 Michael L. Young (license 5026)

Review: https://reviewboard.asterisk.org/r/2444/
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Merged revisions 385593 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 385594 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@385595 65c4cc65-6c06-0410-ace0-fbb531ad65f3