Merge pull request #1123 from nanoric/bitmex_market_price

[Fix] 修正市价单无法下单的问题

vnpy/trader/gateway/bitmexGateway/bitmexGateway.py

@@ -196,6 +196,11 @@ class RestApi(BitmexRestApi):
             'orderQty': orderReq.volume,
             'clOrdID': str(orderId)
         }
+        
+        # 市价单不能有price字段
+        if orderReq.priceType == PRICETYPE_MARKETPRICE:
+            req.pop('price')
+        
         self.addReq('POST', '/order', self.onSendOrder, postdict=req)
         
         return vtOrderID