[Bug 1230192] Docker fails mounting a volume as readonly on files located under /usr

[Red Hat Bugzilla]

https://bugzilla.redhat.com/show_bug.cgi?id=1230192

--- Doc Text *updated* by Daniel Walsh  ---
Cause:

Docker/SELinux code is blocking relabels of /usr, even if user did not request relabel.

Consequence:

Certain volume mounts of content under /usr are blocked and container can not run.
Fix:

Fix the check on relabeling

Result:

Volumes under /usr can be mounted into container.