Fix for Chromedriver not connecting to adb running on non-default port. Take 2

Fixes #3717 
Depends on appium/appium-adb#47 being merged in.
what i'm confused about is in this diff you are adding `this.adb = new ADB(args)`, but you are not using `this.adb` anywhere in this diff. So the question is, if we already use it, why is `this.adb` not already defined?