an X display is required for keycode conversions

[andrcuns]

Looks like xvfb is still needed when running tests with chromedriver even on real device. Here is the error I get:

[debug] [JSONWP Proxy] Got response with status 200: {"sessionId":"79836eb8083f234038177a3804fb0282","status":13,"value":{"message":"unknown error: an X display is required for keycode conversions, consider using Xvfb\n  (Session info: chrome=58.0.3029.83)\n  (Driver info: chromedriver=2.28.455506 (18f6627e265f442aeec9b6661a49fe819aeeea1f),platform=Linux 4.11.2-1-ARCH x86_64)"}}

The issue is mentioned here. I created a fix based on solution mentioned in linked issue, will add PR shortly.

[SrinivasanTarget]

Sure @andrcuns