Don't mount selinux fs in LXC if selinux is disabled

Before trying to mount the selinux filesystem in a container
use is_selinux_enabled() to check if the machine actually
has selinux support (eg not booted with selinux=0)

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
(cherry picked from commit 95c6cc344b)

src/lxc/lxc_container.c

@@ -705,6 +705,12 @@ static int lxcContainerMountBasicFS(bool pivotRoot,
             (access(srcpath, R_OK) < 0))
             continue;
 
+#if WITH_SELINUX
+        if (STREQ(mnts[i].src, SELINUX_MOUNT) &&
+            !is_selinux_enabled())
+            continue;
+#endif
+
         if (virFileMakePath(mnts[i].dst) < 0) {
             virReportSystemError(errno,
                                  _("Failed to mkdir %s"),