Log Message:
cairo-gobject: Bump PKGREVISION

Bump PKGREVISION to nb3.  Despite only 35 minutes passed between the
PKGREVISION++ and PKGREVISION-- at least a bulk builder catched it leading to
failures of building x11/gtk3.  Bump it to nb3 in order to be on the safest
side.

Thanks to <jperkin> and <joerg>! (Possible further regressions are \ 
mine though!)