tsm-client: fix absolute symlinks, drop openssl dependency

`tsm-client` is delivered with its
own `lib{crypto,ssl}.so` implementation.
Beginning with version 8.1.9.1, those `.so`-files came with
absolute symlinks to `/opt/...` causing `autoPatchelf`
to abort with error messages of the form

> error: auto-patchelf could not satisfy dependency libssl.so.1.1

I was under the impression that a new dependency
got introduced and added `openssl` to `builtInputs`
in commit 5ad0ecb9019e964d2abfe034e184f8b846e42dfa.
This fixed the build, but `tsm-client` no longer
linked against its own ssl implementation.

The commit at hand corrects that mistake:
It adds a small `preFixup` script that finds
and adapts absolute symlinks to `/opt/`,
so that `autoPatchelfHook` finds those
`so`-files again and sets RPATH properly.
This permits to drop `openssl` from the dependency list again.

pkgs/tools/backup/tsm-client/default.nix

···
 , autoPatchelfHook
 , rpmextract
 , libxcrypt-legacy
-, openssl
 , zlib
 , lvm2  # LVM image backup and restore functions (optional)
 , acl  # EXT2/EXT3/XFS ACL support (optional)
···
     ];
     buildInputs = [
       libxcrypt-legacy
-      openssl
       stdenv.cc.cc
       zlib
     ];
···
       runHook postInstall
     '';
 
-    # Fix relative symlinks after `/usr` was moved up one level
+    # fix relative symlinks after `/usr` was moved up one level,
+    # fix absolute symlinks pointing to `/opt`
     preFixup = ''
       for link in $out/lib{,64}/* $out/bin/*
       do
···
           exit 1
         fi
         ln --symbolic --force --no-target-directory "$out/$(cut -b 7- <<< "$target")" "$link"
+      done
+      for link in $(find $out -type l -lname '/opt/*')
+      do
+        ln --symbolic --force --no-target-directory "$out$(readlink "$link")" "$link"
       done
     '';
   };

pkgs/top-level/all-packages.nix

···
 
   timeline = callPackage ../applications/office/timeline { };
 
-  tsm-client = callPackage ../tools/backup/tsm-client {
-    openssl = openssl_1_1;
-  };
-  tsm-client-withGui = callPackage ../tools/backup/tsm-client {
-    openssl = openssl_1_1;
-    enableGui = true;
-  };
+  tsm-client = callPackage ../tools/backup/tsm-client { };
+  tsm-client-withGui = callPackage ../tools/backup/tsm-client { enableGui = true; };
 
   tracker = callPackage ../development/libraries/tracker { };