BUG: Don't sort currencies when making fx rates.

This causes the stored currencies to get out of sync with
cls.FX_RATES_CURRENCIES.

Author: Scott Sanderson

zipline/testing/fixtures.py

@@ -2152,8 +2152,6 @@ def make_fx_rates_from_reference(cls, reference):
     def make_fx_rates(cls, rate_names, currencies, sessions):
         rng = np.random.RandomState(42)
 
-        currencies = sorted(currencies)
-
         out = {}
         for rate_name in rate_names:
             cols = {}