Fixes #6242 - remove unused distributor from rabl to fix error.

There was an HTTP 500 on subscription show if you were not admin
(or didn't have the distributor read permission) because distributor
was still referenced from the rabl.  This commit removes the reference.
Merge pull request #4275 from waldenraines/6242

Fixes #6242 - remove unused distributor from rabl to fix error.