Load correct exchange class

closes #2371

freqtrade/resolvers/exchange_resolver.py

@@ -3,7 +3,7 @@ This module loads custom exchanges
 """
 import logging
 
-from freqtrade.exchange import Exchange
+from freqtrade.exchange import Exchange, MAP_EXCHANGE_CHILDCLASS
 import freqtrade.exchange as exchanges
 from freqtrade.resolvers import IResolver
 
@@ -22,6 +22,8 @@ class ExchangeResolver(IResolver):
         Load the custom class from config parameter
         :param config: configuration dictionary
         """
+        # Map exchange name to avoid duplicate classes for identical exchanges
+        exchange_name = MAP_EXCHANGE_CHILDCLASS.get(exchange_name, exchange_name)
         exchange_name = exchange_name.title()
         try:
             self.exchange = self._load_exchange(exchange_name, kwargs={'config': config})