Readd ticker_interval to trade api response

freqtrade/persistence.py

@@ -258,6 +258,7 @@ class Trade(_DECL_BASE):
             'amount': round(self.amount, 8),
             'stake_amount': round(self.stake_amount, 8),
             'strategy': self.strategy,
+            'ticker_interval': self.timeframe,  # DEPRECATED
             'timeframe': self.timeframe,
 
             'fee_open': self.fee_open,

tests/rpc/test_rpc_apiserver.py

@@ -323,6 +323,7 @@ def test_api_show_config(botclient, mocker):
     assert 'dry_run' in rc.json
     assert rc.json['exchange'] == 'bittrex'
     assert rc.json['ticker_interval'] == '5m'
+    assert rc.json['timeframe'] == '5m'
     assert rc.json['state'] == 'running'
     assert not rc.json['trailing_stop']