Please update 'cadabra' and 'modglue' Portfiles

[Kasper Peeters]

Hi,

I have an open issue 

   https://trac.macports.org/ticket/38938

concerning a minor change to the Portfiles to make 'cadabra' work again.
This issue has been idle on the tracker for 3 months and my users keep
complaining that the version in the repos is broken. 

Can someone please have a look and upload it, or let me know what else
needs to be done? Many many thanks!

Cheers,
Kasper