fix: include version_migration in test overrides

Use `libvirt` from repo in `version_migration` tests.

That was missed in
https://gitlab.cyberus-technology.de/cyberus/cloud/libvirt/-/merge_requests/153

On-behalf-of: SAP julian.schindel@sap.com
Signed-off-by: Julian Schindel <julian.schindel@cyberus-technology.de>

Author: arctic-alpaca

flake.nix

@@ -160,11 +160,13 @@
           all_drivers = pkgs.symlinkJoin {
             name = "all-test-drivers";
             paths = with tests; [
+              # Sorted alphabetically.
               default.driver
-              live_migration.driver
               hugepage.driver
+              live_migration.driver
               long_migration_with_load.driver
               numa_hosts.driver
+              version_migration.driver
             ];
           };
         }