Restore setting of sensors interface.

Change I5c1bf3999ad2268c0dba9b3fe511d999c2e63fd9's forward porting from Qt 5.1
removed this, thus the interface was never set, thus sensors all broke.

Change-Id: If3b14b5ebd20e6cb64bc2000b23a2c1e37d36b05
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>