Set height to -1 for unconfirmed keva_put.

src/rpc/rpckeva_nonwallet.cpp

@@ -115,6 +115,7 @@ UniValue keva_get(const JSONRPCRequest& request)
       UniValue obj(UniValue::VOBJ);
       obj.pushKV("key", keyStr);
       obj.pushKV("value", ValtypeToString(val));
+      obj.pushKV("height", -1);
       return obj;
     }
   }