Travis: Reduce build matrix

Author: lgeiger

.travis.yml

@@ -1,6 +1,4 @@
 language: node_js
-node_js:
-  - "6"
 sudo: false
 
 addons:
@@ -11,15 +9,18 @@ addons:
     - gcc-4.9
     - g++-4.9
 
-os:
-  - linux
-  - osx
-
+matrix:
+  include:
+    - node_js: "6"
+      env: DEPLOY="true"
+    - node_js: "6"
+      env: ELECTRON="1.1.3"
+    - node_js: "6"
+      env: ELECTRON="1.4.4" REBUILD="true"
+    - os: osx
+      node_js: "6"
+      env: DEPLOY="true"
 env:
-  matrix:
-    - 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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