[FIX] Send URI is defaulting to XRP (not the correct currency) (RT-2060)

[RT-2060](https://ripplelabs.atlassian.net/browse/RT-2060)
[BS](https://www.bountysource.com/issues/3592182-ripple-trade-send-uri-is-defaulting-to-xrp-not-the-correct-currency)