Do not use 'MozDontOfferDataChannel' attribute on Chrome

git-svn-id: http://sipml5.googlecode.com/svn/trunk@180 63d8a0da-676c-2731-e3aa-b417aa27da68
API update for click2dial.org project

git-svn-id: http://sipml5.googlecode.com/svn/trunk@182 63d8a0da-676c-2731-e3aa-b417aa27da68