Move .title to ExchangeResolver (it does not make sense to do this over

and over again)

freqtrade/optimize/backtesting.py

@@ -63,8 +63,7 @@ class Backtesting(object):
         self.config['dry_run'] = True
         self.strategylist: List[IStrategy] = []
 
-        exchange_name = self.config.get('exchange', {}).get('name').title()
-        self.exchange = ExchangeResolver(exchange_name, self.config).exchange
+        self.exchange = ExchangeResolver(self.config['exchange']['name'], self.config).exchange
         self.fee = self.exchange.get_fee()
 
         if self.config.get('runmode') != RunMode.HYPEROPT: