MBS-6553, add error handling to relationship/:mbid/edit
MBS-6553, changes based on pull request feedback.

- use &#xa0; instead of &nbsp;
- use !(a || b) instead of !a && !b.
Merge branch 'mbs-6553' into beta

* mbs-6553:
  MBS-6553, changes based on pull request feedback.
  MBS-6553, add error handling to relationship/:mbid/edit

Conflicts:
	postgresql-musicbrainz-collate
	postgresql-musicbrainz-unaccent