Separate HaveKey function that checks whether a key is in a keystore

src/keystore.cpp

@@ -195,3 +195,10 @@ CKeyID GetKeyForDestination(const CKeyStore& store, const CTxDestination& dest)
     }
     return CKeyID();
 }
+
+bool HaveKey(const CKeyStore& store, const CKey& key)
+{
+    CKey key2;
+    key2.Set(key.begin(), key.end(), !key.IsCompressed());
+    return store.HaveKey(key.GetPubKey().GetID()) || store.HaveKey(key2.GetPubKey().GetID());
+}