retry without partial data after a 416 response

retry without partial data after a 416 response

If we get a 416 from the server it means the Range we asked for is above
the real filesize of the file on the server. Mostly this happens if the
server isn't supporting If-Range, but regardless of how we end up with
the partial data, the data is invalid so we discard it and retry with a
fresh plate and hope for the best.

Old behavior was to consider 416 an error and retry with a different
compression until we ran out of compression and requested the
uncompressed file (which doesn't exist on most mirrors) with an accept
line which server answered with "406 Not Acceptable".

Closes: 710924