Add echo no before npm install -g nativescript

Author: DimitarTodorov

.travis.yml

@@ -195,6 +195,6 @@ before_install:
   - sudo pip install six
 
 install:
-  - npm install -g nativescript
+  - echo no | npm install -g nativescript
   - tns usage-reporting disable
   - tns error-reporting disable