Fix hgweb.filediff
The third argument to hgweb.diff should be a list, not a string.
This fixes a bug found by xorAxAx, where hgweb would also show the diff
for "README" when you ask for the diff for "Demo/cgi/README".
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