[RndTbl] muug paypal urls reset

[Trevor Cordes]

Due to a bug in how paypal links contained in the renewal notices were
generated, we have had to update the system a bit.  This invalidates all
existing paypal links you may have received prior to today.  Links in
subsequent (post-Apr20) renewal emails will be valid.

If you want to use paypal to renew, you can request a new link to be
issued to you immediately by emailing: membership at muug.ca

The bug caused a very small number of users (about a 1 in 256) to see an
error page when they tried to use their link.  If you encountered this
problem, we apologize for the inconvenience.