Delete Payment Disclosures

This code will be "experimental" forever, only supports Sprout, and
is a piece of shit. Deleting with fire.

Sapling viewing keys are the replacement, which already exist.

src/wallet/asyncrpcoperation_shieldcoinbase.h

@@ -34,8 +34,6 @@
 
 #include <univalue.h>
 
-#include "paymentdisclosure.h"
-
 // Default transaction fee if caller does not specify one.
 #define SHIELD_COINBASE_DEFAULT_MINERS_FEE   10000
 
@@ -81,8 +79,6 @@ public:
     bool testmode = false;  // Set to true to disable sending txs and generating proofs
     bool cheatSpend = false; // set when this is shielding a cheating coinbase
 
-    bool paymentDisclosureMode = true; // Set to true to save esk for encrypted notes in payment disclosure database.
-
 private:
     friend class ShieldToAddress;
     friend class TEST_FRIEND_AsyncRPCOperation_shieldcoinbase;    // class for unit testing
@@ -110,9 +106,6 @@ private:
     void lock_utxos();
 
     void unlock_utxos();
-
-    // payment disclosure!
-    std::vector<PaymentDisclosureKeyInfo> paymentDisclosureData_;
 };
 
 class ShieldToAddress : public boost::static_visitor<bool>