Reverts rev 316218 as it breaks parsing the [general] section of sip.conf.

The functionality this patch attempts to achieve should already
be possible using [general](+) in the config file.

issue #17957



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@316798 65c4cc65-6c06-0410-ace0-fbb531ad65f3