travis: don't test Python 3.4
travis: don't test Python 3.4

Beancount will start supporting 3.5 only with the next release.

yagebu/fava,beancount/fava,aumayr/beancount-web,yagebu/fava,aumayr/beancount-web,beancount/fava,yagebu/fava,yagebu/fava,aumayr/beancount-web,beancount/fava,aumayr/beancount-web,yagebu/fava,beancount/fava,beancount/fava