try to fix build

.travis.yml

@@ -30,7 +30,6 @@ before_cache:
   - rm -rf $HOME/.gradle/caches/*/plugin-resolution/
 
 install:
-  - netstat -vanp tcp | grep 8081
   # node
   - curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.1/install.sh | bash
   - export NVM_DIR="$HOME/.nvm" && [ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"