storage capacity: fix description of CSIDriver field rollback

The implementation in the apiserver already preserves the field and
delivers it to clients, which is the exact opposite of how it was
described in the KEP.

Author: pohly

keps/sig-storage/1472-storage-capacity-tracking/README.md

@@ -856,9 +856,11 @@ enhancement:
   objects: this needs to be treated with exponential backoff just like other
   communication issues with the API server.
 
-  The new flag in `CSIDriver` will always be removed when disabling the
-  feature gate or when rolling back to a release older than 1.19. In that
-  case kube-scheduler will revert to provisioning without capacity information.
+  The new flag in `CSIDriver` will be preserved when disabling the
+  feature gate or when rolling back to a release older than 1.19. kube-scheduler
+  will continue to do scheduling with capacity information until it also
+  gets rolled back to a version without support for that or the feature
+  is turned off for kube-scheduler.
 
 * **What happens if we reenable the feature if it was previously rolled back?**