cvsps: fix traceback involving 'synthetic'
https://bugzilla.redhat.com/show_bug.cgi?id=573666
Reported by Sjoerd Mullender
Basic install: $ make # see install targets $ make install # do a system-wide install $ hg debuginstall # sanity-check setup $ hg # see helpSee http://mercurial.selenic.com/ for detailed installationinstructions, platform-specific notes, and Mercurial user information.