Bump Ubuntu version for CI, remove unused option (#631)

Author: nowaktz

.travis.yml

@@ -1,5 +1,4 @@
-sudo: false
-dist: precise
+dist: bionic
 language: ruby
 rvm:
 - 2.2
@@ -9,7 +8,7 @@ install:
   - "node --version"
   - "npm --version"
   - "npm install"
-script: "travis_wait gulp build:full"
+script: "travis_wait node_modules/.bin/gulp build:full"
 before_deploy:
   - mkdir _codedeploy
   - tar czf _codedeploy/dev-opera.tar.gz appspec.yml dest