At @mikeb's suggestion in the code review, this makes HiddenUsers plural.
This makes the whole changeset a little more invasive than it was before, so please review carefully.
This adds new query arguments to the taskList hub xmlrpc endpoint, and then
makes use of those arguments in koji-web. A new optional configuration value
is added for koji-web: `HiddenUser`, which can be used to specify which user
account should be hidden. This could be useful for deployments that have a
continuous-integration account, the spam from which makes the frontpage
difficult to read.
Unit test cases are also added for some functions of the hub taskList endpoint.
Signed-off-by: Ralph Bean <rbean@redhat.com>
