VCS::vcs_mirror does not clean up untracked files

[nickanderson]

% svn status
?       file

% /var/cfengine/bin/cf-agent  -KIf /home/cmdln/.cfagent/inputs/standalone-cf-sketch-runfile.cf
 -> Executing '/usr/bin/svn cleanup' ... (no timeout,uid=1000)
 -> Completed execution of /usr/bin/svn cleanup
 -> Executing '/usr/bin/svn up' ... (no timeout,uid=1000)
Q: "...sr/bin/svn up": Updating '.':
Q: "...sr/bin/svn up": At revision 98.
I: Last 2 quoted lines were generated by promiser "/usr/bin/svn up"
 -> Completed execution of /usr/bin/svn up
 -> Executing '/usr/bin/svn revert /tmp/svn_co' ... (no timeout,uid=1000)
 -> Completed execution of /usr/bin/svn revert /tmp/svn_co
R: Not creating parent path /tmp even though it doesn't exist, because the parent_dir parameter was left blank.
 !! Method invoked repairs

% pwd
/tmp/svn_co/masterfiles

% svn status
?       file

Untracked files should be deleted.

svn status | grep '^?' | awk '{print $2}' | xargs rm -rf