cdr: Change the number of container buckets to be similar to the channels container.

* Fix the temporary cdr candidate containers to use a prime number of
buckets.
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Merged revisions 398579 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@398583 65c4cc65-6c06-0410-ace0-fbb531ad65f3