do parse defaultlanguage from asterisk.conf

Do parse the option "defaultlanguage" from the [options] section of
asterisk.conf, as in the sample config file. Otherwise the build-time
default language (normally "en") is always the default one.

Review: https://reviewboard.asterisk.org/r/1342/


Signed-off-by: Tzafrir Cohen (License #5035) <tzafrir.cohen@xorcom.com>
Original-Commit: http://svn.digium.com/svn/asterisk/branches/1.8@335716
Original-Commit: http://svn.digium.com/svn/asterisk/branches/10@335717

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@335718 65c4cc65-6c06-0410-ace0-fbb531ad65f3