Remove validation cookie support code

src/ripple/protocol/STValidation.h

@@ -117,7 +117,6 @@ public:
         @param isFull Whether the validation is full or partial
         @param fee FeeSettings to include in the validation
         @param amendments If not empty, the amendments to include in this validation
-        @param cookie If not none, the validation cookie to set
 
         @note The fee and amendment settings are only set if not boost::none.
               Typically, the amendments and fees are set for validations of flag
@@ -133,8 +132,7 @@ public:
         NodeID const& nodeID,
         bool isFull,
         FeeSettings const& fees,
-        std::vector<uint256> const& amendments,
-        boost::optional<std::uint64_t> const cookie);
+        std::vector<uint256> const& amendments);
 
     STBase*
     copy(std::size_t n, void* buf) const override