Set OPTIONS_UNSET in the argument list to env(1), and add

AVAHI to the list.  This fixes the textproc/docproj build
seemingly following FLAVORS being added.

Specifically, the problem with the dependency chain here is:
- textproc/docproj depends on print/cups, which sets AVAHI=on
  by default;
- net/avahi-app depends on devel/gobject-introspection, which
  requires python3+;
- graphics/netpbm depends on graphics/mesa-libs, which can
  only be built with python2.7;
- textproc/docproj depends on a number of graphics ports for
  font rendering, etc.

MFC after:	3 days
MFC before:	12.0-BETA3
Sponsored by:	The FreeBSD Foundation

release/release.sh

@@ -287,9 +287,9 @@ extra_chroot_setup() {
 			PBUILD_FLAGS="${PBUILD_FLAGS} OSREL=${REVISION}"
 			PBUILD_FLAGS="${PBUILD_FLAGS} WRKDIRPREFIX=/tmp/ports"
 			PBUILD_FLAGS="${PBUILD_FLAGS} DISTDIR=/tmp/distfiles"
-			chroot ${CHROOTDIR} env ${PBUILD_FLAGS} make -C \
+			chroot ${CHROOTDIR} env ${PBUILD_FLAGS} \
+				OPTIONS_UNSET="AVAHI FOP IGOR" make -C \
 				/usr/ports/textproc/docproj \
-				OPTIONS_UNSET="FOP IGOR" \
 				FORCE_PKG_REGISTER=1 \
 				install clean distclean
 		fi