Update CircleCI config

Properly download the script and execute it instead of streaming it to
`sh`.

Author: Arcanemagus

circle.yml

@@ -1,8 +1,8 @@
-test:
+dependencies:
   override:
-    - curl -s https://raw.githubusercontent.com/atom/ci/master/build-package.sh | sh
+    - curl -s -O https://raw.githubusercontent.com/atom/ci/master/build-package.sh
+    - chmod u+x build-package.sh
 
-dependencies:
+test:
   override:
-    # If nothing is put here, CircleCI will run `npm install` using the system Node.js
-    - echo "Managed in the script"
+    - ./build-package.sh