Turns out the default VM images have basic support to handle even
multipathing. But might not contain the actual bits to enable the
kernel initial ramdisk to be regenerated at a later point in time
with those artifacts.
This creates a situation where a user could deploy the image on a
physical host, make other changes or perform an upgrade later, and
suddenly loose the ability to boot via multipath.
Alternatively, it also creates a situation where resulting DIB
images may explicitly loose multipath support where the base image
worked just fine.
Change-Id: I8e165cf65b1d5db4bcad3264b5c2b098db84fbb8
6739fa8ef4