Fixed enablement of Save/Reset button on RHN Updates tab.

- Changed haml view to pass in id on default buttons and some of the fields that were missing that, id is used to load @edit from session using load_edit method.
- Changed edit_rhn method to save initial data in @edit[:current] so it can be used to determine whether to enable/disable save/reset buttons on screen.
- Removed code from "reset_repo_name_from_default" method that was setting values directly into session[:edit] hash, changed it to return the default repo name and let "settings_get_form_vars" save the data in @edit[:new] hash.

Issue #254