Do not try to preserve permissions when copying to the -i installdir

in the METALOG case (it makes no sense at all).

distrib/sets/maketars

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# $NetBSD: maketars,v 1.81 2015/04/26 09:21:36 martin Exp $
+# $NetBSD: maketars,v 1.82 2015/05/26 15:46:01 martin Exp $
 #
 # Make release tar files for some or all lists.  Usage:
 # maketars [-b] [-x] [-i installdir] [-a arch] [-m machine] [-s setsdir]
@@ -213,11 +213,16 @@ runpax() {
 GZIP=-9n		# for pax -z
 export GZIP
 es=0
+preserve=
+if [ -n "${metalog}" ]; then
+	preserve="-pe"
+fi
+
 for setname in ${lists:-${nlists}}; do
 	out="${setname}.tgz"
 	if [ -n "${installdir}" ]; then
 		msg "Copying set ${setname}"
-		runpax "${setname}" -rpe "${installdir}"
+		runpax "${setname}" -r ${preserve} "${installdir}"
 	else
 		if [ -n "${metalog}" -a "${tars}/${out}" -nt "${metalog}" ]
 		then