Christian Ebert <blacktrash@gmx.net> [Wed, 23 Dec 2009 12:04:04 +0000] rev 10116
keyword: do not monkeypatch diff when in restricted mode
kw_diff actually disabled restricted mode when 2 revisions were given,
because it effectively disables the extension in this case.
But the commands working with diff and patch need restricted mode
always enabled, i.e. expansion enabled when writing to the
working directory and - crucial for these commands - no expansion
when reading the filelog.