QNonContiguousByteDevice: roll back complete internal state in reset()

... otherwise we would not start reading from the beginning when the
device was reset.

Change-Id: I897adbad6e1f240fa871758ec7e3d6b499cb5944
(cherry-picked from commit ffe45f1896adfff93258b917f6a566dcc06a6597)
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>