Bug#299622: Update with suggested solutions

[John Winters <john@sinodun.org.uk>]

I've now spent some time tracing exactly what the code is doing and know
what is causing the problems.

1) The code which purports to check the md5sum doesn't actually do
exactly that.  Instead it checks that the whole line in the .md5sum file
matches with what it expects.  You can thus have the odd situation where
the md5sum matches but the rest of the line doesn't and so the check
fails.  This could be fixed either by comparing just the first field of
each (the md5sum itself) or by updating the documentation to make it
clear that the full path must be used when re-generating the .md5sum
file.  I would suggest that the former approach is the better fix,
because there are lots of valid ways of referencing any file, even if
you insist on an absolute reference.

2) The code does actually attempt to issue a message explaining why it
hasn't written the file, but the message is by default suppressed.  I
would suggest that a message which is trying to say, "I'm not going to
do what you asked me to do because..." warrants a status (on the
"Information", "Warning", "Error", "Severe error" scale) of at least
"Warning".  By using "warn" instead of "observe" the message would at
least appear and much bafflement could be avoided.

I hope this is useful input.

Regards,
John Winters