remove node_modules cache

.travis.yml

@@ -3,9 +3,6 @@ services:
   - redis-server
 before_install:
   - cp install/package.json package.json
-cache:
-  directories:
-    - node_modules
 before_script:
   - sleep 15 # wait for mongodb to be ready
   - sh -c "if [ '$DB' = 'mongodb' ]; then node app --setup=\"{\\\"url\\\":\\\"http://127.0.0.1:4567\\\",\\\"secret\\\":\\\"abcdef\\\",\\\"database\\\":\\\"mongo\\\",\\\"mongo:host\\\":\\\"127.0.0.1\\\",\\\"mongo:port\\\":27017,\\\"mongo:username\\\":\\\"\\\",\\\"mongo:password\\\":\\\"\\\",\\\"mongo:database\\\":0,\\\"admin:username\\\":\\\"admin\\\",\\\"admin:email\\\":\\\"test@example.org\\\",\\\"admin:password\\\":\\\"abcdef\\\",\\\"admin:password:confirm\\\":\\\"abcdef\\\"}\" --ci=\"{\\\"host\\\":\\\"127.0.0.1\\\",\\\"port\\\":27017,\\\"database\\\":0}\"; fi"