chore(travis): run npm install twice

This is not optimal solution at all, but I can’t think of any better.

Author: vojtajina

.travis.yml

@@ -20,7 +20,8 @@ env:
 
 install:
   - npm config set registry http://23.251.144.68
-  - npm install
+  # Run npm install twice, because it is flaky.
+  - npm install || npm install
 
 before_script:
   - mkdir -p $LOGS_DIR