Travis: Simplify node install

Author: lgeiger

.travis.yml

@@ -1,4 +1,6 @@
-language: c
+language: node_js
+node_js:
+  - "6"
 sudo: false
 
 addons:
@@ -15,9 +17,9 @@ os:
 
 env:
   matrix:
-    - NODE_VERSION="6" DEPLOY="true"
-    - NODE_VERSION="6" ELECTRON="1.1.3"
-    - NODE_VERSION="6" ELECTRON="1.4.4" REBUILD="true"
+    - DEPLOY="true"
+    - ELECTRON="1.1.3"
+    - ELECTRON="1.4.4" REBUILD="true"
   global:
     - GH_REF: github.com/nteract/zmq-prebuilt.git
     - secure: 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
@@ -26,10 +28,6 @@ before_install:
   - export DISPLAY=':99.0'
   - Xvfb :99 -screen 0 1024x768x24 > /dev/null 2>&1 &
   - test "$(uname)" = "Darwin"  || export CXX=g++-4.9 CC=gcc-4.9
-  - curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.30.2/install.sh | bash
-  - source ~/.nvm/nvm.sh
-  - nvm install $NODE_VERSION
-  - nvm use $NODE_VERSION
 
 install:
   - npm install