To be able to update content of the function to other access modes when we implement SELinux mount for more of them.
github.com/opencontainers/selinux/go-selinux needs OS that supports SELinux and SELinux enabled in it to return useful data, therefore add an interface in front of it, so we can mock its behavior in unit tests.
Both ActualStateOfWorld and DesiredStateOfWorld must track SELinux context of volume mounts.