Ignore failure to mount SELinux filesystem in container

User namespaces will deny the ability to mount the SELinux
filesystem. This is harmless for libvirt's LXC needs, so the
error can be ignored.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/lxc/lxc_container.c

@@ -741,6 +741,12 @@ static int lxcContainerMountBasicFS(void)
         VIR_DEBUG("Mount %s on %s type=%s flags=%x, opts=%s",
                   srcpath, mnts[i].dst, mnts[i].type, mnts[i].mflags, mnts[i].opts);
         if (mount(srcpath, mnts[i].dst, mnts[i].type, mnts[i].mflags, mnts[i].opts) < 0) {
+#if WITH_SELINUX
+            if (STREQ(mnts[i].src, SELINUX_MOUNT) &&
+                (errno == EINVAL || errno == EPERM))
+                continue;
+#endif
+
             virReportSystemError(errno,
                                  _("Failed to mount %s on %s type %s flags=%x opts=%s"),
                                  srcpath, mnts[i].dst, NULLSTR(mnts[i].type),