It is possible that if device creation fails that the display would be left in
a state where rx::DisplayImpl is initialized and egl::Display is not.

BUG=angleproject:2546

Change-Id: I609e4c40f37945322d64786d4f6e97f361764b62
Reviewed-on: https://chromium-review.googlesource.com/1066501
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>