Please contact TAC. We have an internal process to clear pending deployments but it involves messing with databases. This can wreak havoc with the device if someone doesn't know what they are doing, so it is not public.
Clientless SSL VPN is deprecated in all versions of FTD (and in ASA from 9.17 onwards). Thus, the command to set an access rule for the webvpn portal no longer exists. You can simply remove the FlexConfig object.
