Switch transferdigittimeout to be configured as seconds instead of milliseconds.

This was an unintentional consequence of the update of features.conf to use the
config framework in Asterisk 12. Thanks to Marco Signorini on the Asterisk
developers list for pointing out the problem.
........

Merged revisions 399237 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@399238 65c4cc65-6c06-0410-ace0-fbb531ad65f3