Made reporting of missing refentry metadata more quiet:

Made reporting of missing refentry metadata more quiet:

  - we no longer report anything if usable-but-not-preferred
    metadata is found; we just quietly use whatever we manage to
    find

  - we now only report missing "source" metadata if the refentry
    is missing BOTH "source name" and "version" metadata; if it
    has one but not the other, we use whichever one it has and
    don't report anything as missing

The above changes were made because testing with some "real world"
source reveals that some authors are intentionally choosing to use
"non preferred" markup for some metadata, and also choosing to
omit "source name" or "version" metadata in there DocBook XML. So
it does no good to give them pedantic reminders about what they
already know...

Also, changed code to cause "fixme" text to be inserted in output
in particular cases:

  - if we can't manage to find any "source" metadata at all, we
    now put fixme text into the output

  - if we can't manage to find any "manual" metadata a all, we
    now put fixme text into the output

The "source" and "manual" metadata is necessary information, so
buy putting the fixme stuff in the output, we alert users to the
need problem of it being missing.