Fix idempotency issues in set_bios_attributes

- Added check to see if attribute even exists, if not, it exits.
- Then checks if attribute is already set to value we want to update
  it to. If yes, then it exits and changed=False
- Otherwise updates the attribute and changed=True

lib/ansible/modules/remote_management/redfish/redfish_config.py

@@ -227,8 +227,7 @@ def main():
 
     # Return data back or fail with proper message
     if result['ret'] is True:
-        del result['ret']
-        module.exit_json(changed=True, msg='Action was successful')
+        module.exit_json(changed=result['changed'], msg=to_native(result['msg']))
     else:
         module.fail_json(msg=to_native(result['msg']))