remove Travis CI extension install because it didn't work, no extension install at the moment
remove Travis CI extension install because it didn't work, no extension install at the moment

Signed-off-by: Henrique Vicente <d390f26e2f50ad5716a9c69c58de1f5df9730e3b@gmail.com>

henvic/vehikel,henvic/vehikel,henvic/vehikel