fix rear mkrescue with sesam 5.x

[abbbi]

hi,

we are evaluating shipping REAR 2.7 with the next sesam release. It appears that with REAR 2.7, mkrescue
step will fail bcs of missing libraries during functionality check:

2022-12-04 12:00:57.066647656 /opt/sesam/bin/sesam/python3/libhogweed.so.6 requires additional libraries (fatal error)
2022-12-04 12:00:57.075641526   linux-vdso.so.1 (0x00007ffc7a5ca000)
                                libnettle.so.8 => not found

adding two more directories to the backup module related LD_LIBRARY_PATH fixes this issue.

[jsmeix]

I "just approve" it because it only affects BACKUP=SESAM which I cannot test.

[jsmeix]

@abbbi
is the change sufficiently backward compatible and fail-safe
in particular when older SESAM versions are used?

For example I don't know if $SM_BIN_SMS has always a value.
If it is unset or has no value the code would evaluate to

SESAM_LD_LIBRARY_PATH=$SM_BIN_SESAM:$SM_BIN_SESAM/python3/:

but I don't know how SESAM_LD_LIBRARY_PATH works
with a trailing colon because "man bash" reads (excerpt)

PATH
...
A zero-length (null) directory name in the value of PATH
indicates the current directory.
A null directory name may appear as two adjacent colons,
or as an initial or trailing colon.

so a trailing colon makes a difference.

[abbbi]

hi,

$SM_BIN_SMS always has a value (its defined in the config file set in sesam2000ini_file)
Older sesam versions will stick to REAR 2.6 which we shipped in past
releases, i dont see an issue here regards backwards compatibility.

Reason for the issues is that SEP has obsoleted python2 to python3, and additional libraries
are now included within the python3 subdirectory. Additionally RTS components need additional
libraries from the SMS subfolder too, to be able to validate.

[jsmeix]

@rear/contributors
provided there are no objections from one of you
I would like to merge it next Wednesday (07. December)
in the afternoon (at Central European Time).

[jsmeix]

@abbbi
I meant when users use a current ReaR with your change
(e.g. from ReaR upstream or from their Linux distributor)
with an older SESAM version.

[abbbi]

@abbbi I meant when users use a current ReaR with your change (e.g. from ReaR upstream or from their Linux distributor) with an older SESAM version.

the change should not cause any issue with older Sesam versions, in fact, i wonder why it didnt report the missing
libraries already with REAR 2.6 (seems the check in REAR 2.7 has seen some rework and is stricter now).
Anyways, our customers will (by default) always use the bundled version.

[jsmeix]

@abbbi
thank you for your continuous contributions to ReaR
in particular for the BACKUP=SESAM method in ReaR!

Contributions for third-party backup tool support in ReaR
are much appreciated because we at ReaR upstream
usually do not have those third-party backup tools
so we totally depend on contributions from people
who use and know about third-party backup tools
(users or ideally even developers).