GetAttributes is called repeatedly while setting the fsGroup of a
volume. Previously, it recalculated whether SELinux was supported during
each call. This resulted in volume.SetVolumeOwnership taking a long
time, delaying pod startup for high file count volumes.
This change checks the SELinux status once, right after node publish,
allowing GetAttributes to simply build and return a struct.
Signed-off-by: John Strunk <jstrunk@redhat.com>
55881f2fc4