⚡ Default NODE_ENV to production

`npm start` will always explicitly set NODE_ENV=development.

So if it's not set, the app is being run outside of the
active dev context.

This way we'll be able to start filtering exception
reports more easily from stuff we should really pay attention to.

Author: imlucas

src/bugsnag.js

@@ -39,10 +39,6 @@ module.exports = bugsnag;
  *   https://github.com/bugsnag/bugsnag-js#user
  */
 module.exports.listen = function listen() {
-  if (!process.env.NODE_ENV) {
-    process.env.NODE_ENV = 'development';
-  }
-
   _.assign(bugsnag, {
     apiKey: TOKEN,
     autoNotify: true,

src/electron/index.js

@@ -1,3 +1,6 @@
+if (!process.env.NODE_ENV) {
+  process.env.NODE_ENV = 'production';
+}
 // Start crash-reporter asap so if anything goes
 // wrong, we can at least view the crash reports
 // locally.  When a crash occurs, a `.dmp` file