When building in priviledged mode, remove the entry for the output file

from etc/mtree/set.* - it may exist and contain stale data.

distrib/sets/maketars

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# $NetBSD: maketars,v 1.98 2023/11/08 13:02:47 christos Exp $
+# $NetBSD: maketars,v 1.99 2024/01/29 15:56:49 martin Exp $
 #
 # Make release tar files for some or all lists.  Usage:
 # maketars [-b] [-x] [-i installdir] [-a arch] [-m machine] [-s setsdir]
@@ -198,7 +198,8 @@ for setname in ${lists}; do
 		# We deliberately do not add set.${setname} to ${metalog},
 		# because we depend on it as an input.
 	else
-		${MTREE} -c -p "${dest}" -k all -R "${skipkeys}" \
+		${MTREE} -c -p "${dest}" -k all \
+		    -R "${skipkeys},set.${setname}" \
 		    -N "${etcdir}" -O "${SDIR}/flist.${setname}" \
 		    | ${MTREE} -C -k all -N "${etcdir}" \
 		    > "${setlistdir}/set.${setname}"