Call PRE and POST with same args as zfs-rsync.sh

we were just passing the hostname. Adding extra args should
not impact any existing script, but will let us write better/
more maintainable/deduplicated PRE scripts

ROOT/DEBIAN/control

@@ -3,6 +3,6 @@ Priority: optional
 Section: otherosfs
 Maintainer: Chemistry COs <support@ch.cam.ac.uk>
 Architecture: all
-Version: 0.9-ch81
+Version: 0.9-ch82
 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/zfs-rsync.sh

@@ -33,11 +33,11 @@ fi
 
 # Prepare the host if required
 if [ ! -z "$PRE" ] ; then
- $PRE $HN >>$LOGDIR/${HN}_${TAG}-pre.log 2>&1
+ $PRE $HN $SRC $DST >>$LOGDIR/${HN}_${TAG}-pre.log 2>&1
 
  PRE_EXIT=$?
  if [ $PRE_EXIT -ne 0 ] ; then
-   echo PRE script $PRE exited with $PRE_EXIT >>$LOGFILE
+   echo PRE script $PRE $HN $SRC $DST exited with $PRE_EXIT >>$LOGFILE
    exit $PRE_EXIT
  fi
 
@@ -75,6 +75,6 @@ then
 fi
 # We should always tidy up.
 if [ ! -z "$POST" ] ; then
- $POST $HN >>$LOGDIR/${HN}_${TAG}-post.log 2>&1
+ $POST $HN $SRC $DST >>$LOGDIR/${HN}_${TAG}-post.log 2>&1
 fi
 exit $EXIT