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.

component/wendelin.core/activate-WC2-preview.cfg

@@ -11,4 +11,4 @@
 [wendelin.core-repository]
 repository = https://lab.nexedi.com/kirr/wendelin.core.git
 branch   = t
-revison  =
+revision =