Do not specify node version in .travis.yml

That way, travis uses the version specified in .nvmrc

services/web/.travis.yml

@@ -1,8 +1,5 @@
 language: node_js
 
-node_js:
-    - "0.10"
-
 before_install:
     - npm install -g grunt-cli
 
@@ -16,4 +13,3 @@ script:
 services:
     - redis-server
     - mongodb
-