remove over-escaped non-breaking spaces

linguist is not able to work with correct non-breaking spaces (cf.
QTBUG-6300 and QTBUG-35652), so we'll have to do entirely without them
for the time being.

Change-Id: Icd36556e141125335899e458102ade5728c6fbaf
Reviewed-by: Guillaume Belz <guillaume.belz@gmail.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>