configure.ac: say 'no' not 'none' when webkit is not detected during autogen.
configure.ac: say 'no' not 'none' when webkit is not detected during autogen.

tasn/elementary,rvandegrift/elementary,tasn/elementary,tasn/elementary,rvandegrift/elementary,rvandegrift/elementary,tasn/elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,FlorentRevest/Elementary,tasn/elementary,FlorentRevest/Elementary,rvandegrift/elementary