tmpfiles now has a new line type, X, which is similar to the x line type
used by the cleanup function.
This is not supported yet by OpenRc, because we do not have the cleanup
function in tmpfiles.sh, so I have added a dummy procedure for it so
we don't get complaints about this line type.
Reported-by: mgorny@gentoo.org
X-Gentoo-Bug: 460880
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=460880