appliance: Add back libldm (ldmtool) and libxml2 to package list

Commit 133a491677 ("Use guestfsd binary to auto-generate library
dependencies for appliance", October 2020) removed explicit
dependencies for various system packages that the daemon links
directly to, ie. all of these libraries:

$ objdump -p daemon/guestfsd | grep NEEDED | sort
  NEEDED               libacl.so.1
  NEEDED               libaugeas.so.0
  NEEDED               libcap.so.2
  NEEDED               libc.so.6
  NEEDED               libgcc_s.so.1
  NEEDED               libhivex.so.0
  NEEDED               libjansson.so.4
  NEEDED               libm.so.6
  NEEDED               libpcre2-8.so.0
  NEEDED               librpm.so.9
  NEEDED               libselinux.so.1
  NEEDED               libsystemd.so.0
  NEEDED               libtirpc.so.3
(plus libyara which I don't have installed.)

This avoids having to update these dependencies if they change, eg.
when we switched from PCRE to PCRE2 we did not need to update this
file.

However the same commit also incorrectly removed two apparent library
packages (libldm, libxml2) which the daemon does not link to, but
which we'd like to pull in because of tools they provide, in
particular ldmtool.

Re-add those two explicit dependencies.

Fixes: commit 133a491677
(cherry picked from commit d5472a2219)

appliance/packagelist.in

@@ -34,6 +34,7 @@ ifelse(REDHAT,1,
   iproute
   iputils
   kernel
+  libldm
   nilfs-utils
   ntfsprogs
   ntfs-3g
@@ -173,6 +174,7 @@ ifelse(MAGEIA,1,
   hfsplus-tools
   iproute2
   iputils
+  libldm
   dnl syslinux uses mtools without depending on it
   mtools
   nilfs-utils
@@ -196,6 +198,7 @@ ifelse(OPENMANDRIVA,1,
   grub2
   iproute2
   iputils
+  libldm
   dnl syslinux uses mtools without depending on it
   mtools
   nilfs-utils
@@ -230,6 +233,7 @@ gzip
 jfsutils
 kmod
 less
+libxml2
 lsof
 lsscsi
 lvm2