* Address chan_dahdi.conf dahdichan option todo item about needing line
number.
* Make ignore_failed_channels option also apply to dahdichan option.
* Don't attempt to create a default pseudo channel if the chan_dahdi.conf
channel/channels option is not allowed.
* Add a similar check for dahdichan in normal chan_dahdi.conf sections as
is done in users.conf.
git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@331955 65c4cc65-6c06-0410-ace0-fbb531ad65f3