Fix now(tz)

now(tz) should return the same time utcnow returns adjusted by whatever
offset is contained by tz. Currently, the offset to freeze_time is also
added, which is removed by this change

Closes #405

freezegun/api.py

@@ -419,7 +419,7 @@ def timestamp(self):
     def now(cls, tz=None):
         now = cls._time_to_freeze() or real_datetime.now()
         if tz:
-            result = tz.fromutc(now.replace(tzinfo=tz)) + cls._tz_offset()
+            result = tz.fromutc(now.replace(tzinfo=tz))
         else:
             result = now + cls._tz_offset()
         return datetime_to_fakedatetime(result)