Fix: don't override the new non-cosmetic default pen in qwidget

Fix: don't override the new non-cosmetic default pen in qwidget

As QWidget initializes any painter created in paintevent handler to
have the pen color of the palette's foreground, setting it to 0 width,
i.e. cosmetic, it negated the effect of the recent change to default
1-width non-cosmetic, ref. I04d910e9700baf7f13a8aac07a3633014bb9283e

This caused scaled painting with default pen on QImage and QWidget
to yield different results.

Change-Id: I930b64bf7c0a8c84b9ea3edb49adc813370fed0e
Reviewed-by: Samuel Rødal <samuel.rodal@digia.com>