Hyperopt had BTC hard coded in the result. This commit will display
the real stake_currency used.
If you used `"stake_currency": "USDT",` in your config file.
Before this commit you saw a message like:
"2 trades. Avg profit 0.13%. Total profit 0.00002651 BTC (0.0027Σ%). Avg duration 142.5 mins."
Now with the commit, we fix the wrong BTC currency:
"2 trades. Avg profit 0.13%. Total profit 0.00002651 USDT (0.0027Σ%). Avg duration 142.5 mins."
fe8ff1b929