replace deprecated tempfile call with mktemp

tempfile is a debian-ism and jammy warns us that use is deprecated.
mktemp has been available on all our debian/ubuntu machines for a long time
via coreutils (e.g. it was definitely in wheezy and trusty, and I'm pretty
sure since before then too)

ROOT/DEBIAN/control

@@ -3,6 +3,6 @@ Priority: optional
 Section: otherosfs
 Maintainer: Chemistry COs <support@ch.cam.ac.uk>
 Architecture: all
-Version: 0.9-ch99
+Version: 0.9-ch100
 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, libformat-human-bytes-perl
 Description: a backup system using ZFS (repository 'backup-scheduler')

ROOT/etc/chem-zfs-backup-server/zfs-rsync.d/prepare

@@ -25,9 +25,9 @@ if $SSH root@$SERVER [ /var/lib/dpkg/status -nt /var/adm/backup/package-files ]
   set -e
   set -o pipefail
   umask 077
-  FILELIST=\`tempfile\`
-  CONFLIST=\`tempfile\`
-  DIFFLIST=\'tempfile\'
+  FILELIST=\`mktemp\`
+  CONFLIST=\`mktemp\`
+  DIFFLIST=\'mktemp\'
   mkdir -p /var/adm/backup
   # Which packages are installed?
   dpkg --get-selections | awk ' { print \$1 ; } ' >/var/adm/backup/packages

ROOT/etc/chem-zfs-backup-server/zfs-rsync.d/prepare-ignore-mysql

@@ -27,8 +27,8 @@ if $SSH root@$SERVER [ /var/lib/dpkg/status -nt /var/adm/backup/package-files ]
  # Need to rebuild package-files
  $SSH root@$SERVER "
   umask 077
-  FILELIST=\`tempfile\`
-  CONFLIST=\`tempfile\`
+  FILELIST=\`mktemp\`
+  CONFLIST=\`mktemp\`
   mkdir -p /var/adm/backup
   # Make logrotate use datestamps
   if ! grep -q dateext /etc/logrotate.conf ; then sed  -i 's/^include/dateext\ninclude/' /etc/logrotate.conf ; fi

ROOT/etc/chem-zfs-backup-server/zfs-rsync.d/prepare-ignore-mysql-and-postgres

@@ -27,8 +27,8 @@ if $SSH root@$SERVER [ /var/lib/dpkg/status -nt /var/adm/backup/package-files ]
  # Need to rebuild package-files
  $SSH root@$SERVER "
   umask 077
-  FILELIST=\`tempfile\`
-  CONFLIST=\`tempfile\`
+  FILELIST=\`mktemp\`
+  CONFLIST=\`mktemp\`
   mkdir -p /var/adm/backup
   # Make logrotate use datestamps
   if ! grep -q dateext /etc/logrotate.conf ; then sed  -i 's/^include/dateext\ninclude/' /etc/logrotate.conf ; fi

ROOT/etc/chem-zfs-backup-server/zfs-rsync.d/prepare2

@@ -17,8 +17,8 @@ if $SSH root@$SERVER [ /var/lib/dpkg/status -nt /var/adm/backup/package-files ]
  # Need to rebuild package-files
  $SSH root@$SERVER "
   umask 077
-  FILELIST=\`tempfile\`
-  CONFLIST=\`tempfile\`
+  FILELIST=\`mktemp\`
+  CONFLIST=\`mktemp\`
   mkdir -p /var/adm/backup
   # Make logrotate use datestamps
   if ! grep -q dateext /etc/logrotate.conf ; then sed  -i 's/^include/dateext\ninclude/' /etc/logrotate.conf ; fi