--selinux-enabled flag should be ignored on Disabled SELinux systems

On Fedora and RHEL we ship selinux-enabled flag in the docker.service config,
but if people setup the /var/lib/docker as btrfs and disable SELinux,
we should not block the daemon from running.

Docker-DCO-1.1-Signed-off-by: Dan Walsh <dwalsh@redhat.com> (github: rhatdan)
Upstream-commit: 9e2eb0f1cc3c4ef000e139f1d85a20f0e00971e6
Component: engine

components/engine/daemon/utils_linux.go

@@ -11,3 +11,7 @@ func selinuxSetDisabled() {
 func selinuxFreeLxcContexts(label string) {
 	selinux.FreeLxcContexts(label)
 }
+
+func selinuxEnabled() bool {
+	return selinux.SelinuxEnabled()
+}