Add a reminder to set a quota on a newly-created backup

I don't think there's a sensible default quota; the value for
a workstation will be very different to a tiny VM, for example.

ROOT/DEBIAN/control

@@ -3,6 +3,6 @@ Priority: optional
 Section: otherosfs
 Maintainer: Chemistry COs <support@ch.cam.ac.uk>
 Architecture: all
-Version: 0.9-ch78
+Version: 0.9-ch79
 Depends: zfs-dkms, postgresql-13 | postgresql-9.5 | postgresql-9.4 , liblockfile-simple-perl, libdbi-perl, libjson-perl, libzfs-perl-chem, libnet-openssh-perl, libdbd-pg-perl, mbuffer, rsync, nfs-kernel-server, pv, libwww-curl-perl
 Description: a backup system using ZFS (repository 'backup-scheduler')

ROOT/usr/lib/chem-zfs-backup-server/new-backup-rsnapshot

@@ -165,3 +165,6 @@ while ! [ -z $1 ] ; do
  shift
 done
 dosql "update host set disabled=false where hostname='$FQDN';"
+
+echo "Please set a quota:"
+echo "  zfs set quota=\$QUOTA $TGT"