Integrated subscription editor tries to make giant dropdown, fails

From the commit:
When trying to edit a subscription using the new 'integrated' editor, it foolishly tries to populate an unfiltered bre dropdown selector. This works OK in test environments, but (as expected) fails miserably with production-size data sets.

The end result is that the dropdown either never populates, or takes a really long time. If the user saves before the dropdown loads, the associated record ID is lost, and the subscription is no longer properly associated with the record.

To fix this, simply turn the dropdown into a disabled text input instead, as the ability to edit this field would generally be more harmful than it is necessary.

branch at:
http://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/dbwells/remove_ssub_bre_dropdown

working/user/dbwells/remove_ssub_bre_dropdown