35coreos-multipath: stop creating incorrect dropin dir

The path used there is incorrect. The dropins dir is
`/etc/multipath/conf.d`:

https://github.com/opensvc/multipath-tools/blob/686797b7d0da4fc24fdfcb0fc6364df78a0b232d/Makefile.inc#L100

But anyway, we don't actually need to create that directory; it's
already in the base image. So just drop it.

overlay.d/05core/usr/lib/dracut/modules.d/35coreos-multipath/coreos-propagate-multipath-conf.sh

@@ -20,6 +20,4 @@ fi
 
 echo "info: propagating initrd multipath configuration"
 cp -v /etc/multipath.conf /sysroot/etc/
-mkdir -p /sysroot/etc/multipath/multipath.conf.d
 coreos-relabel /etc/multipath.conf
-coreos-relabel /etc/multipath/multipath.conf.d