Part of preparations for replacing the array of spans with a list of spans. Review: https://reviewboard.asterisk.org/r/905/ Signed-off-by: Shaun Ruffell <sruffell@digium.com> git-svn-id: http://svn.asterisk.org/svn/dahdi/linux/trunk@9354 a0bf4364-ded3-4de4-8d8a-66a801d63aff