analyze: don't list filesystems among ungrouped that are aliases

analyze: don't list filesystems among ungrouped that are aliases

There are a bunch of filesystems that actually are just aliases for
other filesystems. So far we listed them as "ungrouped", suggesting they
should be added to some file system group. But that's not really
something needed, since they are after all not file systems in their own
right, but aliases only (and usually legacy at that).

hence, let's hide them from display (but debug log about them)