Travis: _actually_ update Django 1.7 to b4
Travis: _actually_ update Django 1.7 to b4

(Oops, Django project changed url convention.)

barseghyanartur/Djrill,barseghyanartur/Djrill,janusnic/Djrill,idlweb/Djrill,brack3t/Djrill,janusnic/Djrill,idlweb/Djrill