create tarball of tempdir files and store it in mailinglist dir

mm2sympa.sh

@@ -98,3 +98,7 @@ if sshml test -r $mmarchive; then
     chmod 644 $localarchive
     $base/import_mbox.sh $localarchive $sympalistname $robot > $tmpdir/archive.log
 fi
+
+# store migration temp data in list dir
+tar=$listdir/mailman2sympa.tar
+(cd $tmpdir && tar -cf $tar * && chown sympa: $tar)