Fix redfish firmware update without progress

The caller opting not to have a callback is no longer a problem
for redfish updates.

Change-Id: I10378bb1d0491e1f446569eb443fa3023b4d2af4

pyghmi/redfish/command.py

@@ -1573,6 +1573,8 @@ class Command(object):
                            update process.  Provide if
          :param bank: Indicate a target 'bank' of firmware if supported
         """
+        if progress is None:
+            progress = lambda x: True
         return self.oem.update_firmware(file, data, progress, bank)
 
     def get_diagnostic_data(self, savefile, progress=None, autosuffix=False):