tests: new test for mq qdiff command
`hg qdiff .' is supposed to work but it is currently broken.
This test should help us verify when it gets fixed.
default = 'changelog'
header = header-rss.tmpl
changelog = changelog-rss.tmpl
changelogentry = changelogentry-rss.tmpl
filelog = filelog-rss.tmpl
filelogentry = filelogentry-rss.tmpl
tags = tags-rss.tmpl
tagentry = tagentry-rss.tmpl