travis.yml: remove restriction to master branch
travis.yml: remove restriction to master branch

We want to be able to build other branches on travis.

Signed-off-by: Heinrich Schuchardt <2cd7bb605d542f55cc27b85da62ad2c96ce31039@gmx.de>

xypron/skyldav,xypron/skyldav,xypron/skyldav,xypron/skyldav