[fix] travis: reomve 'make style' from travis build

Commit 8a16903a removes Makefile target style
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

.travis.yml

@@ -13,7 +13,6 @@ install:
   - make node.env
   - local/py3/bin/pip install codecov
 script:
-  - make styles
   - make themes
   - make test
 after_success: