#10 umask is not used by most tools

[Tim Mann]

vcheckout uses your umask when creating the session
directory, the new version stub, and your
/vesta-work/$USER directory, but (oddly) not when
creating the working directory.

The other repos_ui tools do not look at your umask at
all. They should. See vcheckout for what they should be
doing.

This is somewhere between a bug and a missing feature,
but I chose to file it as a bug.