wallet: Preserve unsupported key origin flags

As originally implemented in PR bitcoin#5916, no longer supported at all.

Author: luke-jr

src/wallet/walletdb.h

@@ -123,13 +123,15 @@ class CKeyMetadata
 {
 public:
     static const int VERSION_BASIC=1;
+    static const int VERSION_WITH_FLAGS = 2;  // not supported, but preserved
     static const int VERSION_WITH_HDDATA=10;
     static const int VERSION_WITH_KEY_ORIGIN = 12;
     static const int CURRENT_VERSION=VERSION_WITH_KEY_ORIGIN;
     int nVersion;
     int64_t nCreateTime; // 0 means unknown
     std::string hdKeypath; //optional HD/bip32 keypath. Still used to determine whether a key is a seed. Also kept for backwards compatibility
     CKeyID hd_seed_id; //id of the HD seed used to derive this key
+    uint8_t unsupported_key_flags;
     KeyOriginInfo key_origin; // Key origin info with path and fingerprint
     bool has_key_origin = false; //!< Whether the key_origin is useful
 
@@ -148,6 +150,8 @@ class CKeyMetadata
         READWRITE(obj.nVersion, obj.nCreateTime);
         if (obj.nVersion >= VERSION_WITH_HDDATA) {
             READWRITE(obj.hdKeypath, obj.hd_seed_id);
+        } else if (obj.nVersion >= VERSION_WITH_FLAGS) {
+            READWRITE(obj.unsupported_key_flags);
         }
         if (obj.nVersion >= VERSION_WITH_KEY_ORIGIN)
         {