Troublesome source URL packaging guideline draft

This is an additional section for:

https://fedoraproject.org/wiki/Packaging/SourceURL

Troublesome URLs
When upstream has URLs for the download that do not end with the tarball name rpm will be unable to parse the tarball out of the source URL. In these cases, you have to put just the tarball's filename into the Source: field. To make clear where you got the tarball, you should leave notes in comments above the Source: line to explain the situation to reviewers and future packagers. Example:

# Mysql has a mirror redirector for its downloads # You can get this tarball by following a link from: # http://dev.mysql.com/downloads/mysql/5.1.html Source0: mysql-5.1.31.tar.gz