fixup! wendelin.core: Add extension to activate Wendelin.core 2 preview

Due to the typo in 6572375c the revision was not unset and so it was
wendelin.core 1 that was still being built and installed.
2 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed SlapOS.SlapRunner.ResilienceTest-Master

00:23:37

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:21:14