Ignore selectByMouse on android until QTBUG-36515 is resolved

At the moment mouse selection on android can make text input
unusable when certain virtual keyboard features are enabled.
This patch will temprorarily disable this feature on
TextField and TextArea until we have a workable solution for
these cases.

Change-Id: Ia04db31d1e83ddfc47bec7519e5a78746e6626a9
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@digia.com>