.travis.yml: Don't test on clean branches.
.travis.yml: Don't test on clean branches.

AlexIljin/factor,AlexIljin/factor,AlexIljin/factor,factor/factor,tgunr/factor,tgunr/factor,bpollack/factor,mrjbq7/factor,bpollack/factor,factor/factor,bpollack/factor,tgunr/factor,factor/factor,factor/factor,factor/factor,tgunr/factor,AlexIljin/factor,tgunr/factor,bpollack/factor,bpollack/factor,mrjbq7/factor,AlexIljin/factor,bpollack/factor,mrjbq7/factor,mrjbq7/factor,AlexIljin/factor,mrjbq7/factor,tgunr/factor,mrjbq7/factor,factor/factor,AlexIljin/factor,bpollack/factor