Description of problem:

Whenever I am running "fedpkg mockbuild" or "mock", I am facing a warning similar to this one, at the very end of such a build job:

...
INFO: Results and/or logs in: /var/lib/mock/fedora-rawhide-x86_64/result
Finish: run
WARNING: unable to delete selinux filesystems (/tmp/mock-selinux-plugin.38oyne4r): [Errno 1] Operation not permitted: '/tmp/mock-selinux-plugin.38oyne4r'
...

Version-Release number of selected component (if applicable):
mock-1.2.15-1.fc23.noarch
selinux-policy-targeted-3.13.1-158.7.fc23.noarch

How reproducible:
Always.

Steps to Reproduce:
1. mock build an arbitrary package and watch the terminal output.


Actual results:
- The warning above
- Each mock run creates a file named /tmp/mock-selinux-plugin.*.
  These are gradually piling up with each mock run.

Additional info:
- This behavior started with today's Fedora update.
- No idea, whether the culprit is mock, selinux or else.