Add guarding logic into reason method of OffsitePayments:Notification, a...

...dd message method to return params['method']

Note: make sure playpass master gemfile is pointing at the correct version/branch of this gem.
I think there might be merit to fully nesting these conditions:
```ruby
if reason_code.present?
  if @@response_codes.has_key? ('r' + reason_code).to_sym
    return reason details from @@response_codes
  else
    return "Unknown error ##{reason_code}"
  end
else
  return nil
end
```