renew shouldn't be implemented as a shell function

[geofft]

Shell functions are annoying for a couple of reasons:

• If your dotfiles are broken, you don't get them
• If you just installed Debathena and didn't start a new shell, you don't get them (this means you can't "renew" and then "blanche $USER -a debathena-announce" right after installing)
• [r24946 tcsh has not yet died in a fire but deserves to]

The reason that renew is a shell function (or alias in tcsh), as I understand it, is to avoid any chance of it searching your path, which might start with a directory in AFS, which might under some circumstances make you very marginally sad if you don't have tokens. But this is easy enough to work around by making it a shell function/alias that just runs /usr/bin/renew to shortcut the path lookup.