fixes spec dependency between rss_feed_data_spec.rb and update_https_spec.rb

[HalahAb]

Resets RssFeedUrl's readonly attributes which are modified after invoking the rake task in update_https_spec.rb, and ensures 'url' is not read only.

[HalahAb]

Resolves #59

[MothOnMars]

@HalaH, this is an interesting case. You’ve actually found a bug in the code, rather than a test issue.

The history of the bug you’ve found is that at the time the update_https rake task was written (ffa833f), url was a read-only attribute for the RssFeedUrl class. So that task removed and then added the url attribute to the readonly_attributes list (ffa833f#diff-49d7b19871b49d356286d27431031aedR76).

A subsequent commit made RssFeedUrl#url not read-only (e0c5ea0#diff-3725379569576e16e22f4f689378dab1L7). So that bug you found is that the update_https task is setting a read-only attribute that should not be read-only, which is breaking rss_feed_data_spec.rb. That’s actually a dangerous bug, because it means that the rake task is erroneously setting the readonly_attributes set for RssFeedUrl.

The fix is two-fold:

1. update the update_https rake task to stop toggling the read-only attributes for RssFeedUrl (because url is no longer read-only for that class
2. prevent any similar problems for FlickrProfile or any other classes. Instead of setting a static array of read-only attributes for the FlickrProfile and RssFeedUrl classes, we should make the code more flexible so that it does not depend on any knowledge of the classes it’s updating. I’m going to close this PR and push a fix for that, because I want to revisit that code and make sure there’s nothing I’m missing in that approach.