Switch travis to python 3.4.
Switch travis to python 3.4.

mozilla/masterfirefoxos,mozilla/masterfirefoxos,craigcook/masterfirefoxos,glogiotatidis/masterfirefoxos,glogiotatidis/masterfirefoxos,mozilla/masterfirefoxos,liu21st/masterfirefoxos,enng0227/masterfirefoxos,enng0227/masterfirefoxos,mozilla/masterfirefoxos,enng0227/masterfirefoxos,liu21st/masterfirefoxos,liu21st/masterfirefoxos,craigcook/masterfirefoxos,glogiotatidis/masterfirefoxos,craigcook/masterfirefoxos,enng0227/masterfirefoxos,craigcook/masterfirefoxos,liu21st/masterfirefoxos,glogiotatidis/masterfirefoxos