Fix order of SIP allow/disallow in MySQL contrib script.

Fix order of SIP allow/disallow in MySQL contrib script.

Using the contrib sippeers.sql script to create the sippeers MySQL table
would result in being unable to place calls if you set the disallow value
to all.

(closes issue ASTERISK-20756)
Reported by: Andre Luis
Patches:
      sippeers.patch patch uploaded by Andre Luis
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Merged revisions 377431 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 377432 from http://svn.asterisk.org/svn/asterisk/branches/10

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@377433 65c4cc65-6c06-0410-ace0-fbb531ad65f3