Attempt to fix chronically failing spec

I _think_ this is happening because we're not waiting for the watcher to start. `nsfw` goes async when the watcher is created _and_ when it's started.

src/config-file.js

@@ -79,7 +79,7 @@ module.exports = class ConfigFile {
           this.requestLoad();
         }
       })
-      watcher.start();
+      await watcher.start();
       return { dispose: () => watcher.stop() };
     } catch (error) {
       //TODO_PULSAR: Find out why the atom global variable isn't available at this point