Fixes #6153, bz1107876 - Fixed cv package excludes publish

Previously if you published a content view with a package excludes
filter with a matching package in the repo. You would get the following
error from pulp (package name is gofer in the example)
pulp.server.webservices.controllers.repositories:ERROR: Error parsing
unassociation criteria [{'fields': {}, 't
ype_ids': ['rpm'], 'filters': {'$or': [{'filename': {'$in':
['gofer-1.2.0-1.el6.noarch.rpm']}}]}}]

This commit fixes that issue.