Remove installed port without /usr/ports directory

[Moritz Schmitt]

Dear all,

Some time ago I installed the port

	security/py-backports.ssl_match_hostname.

Today I updated the ports tree by running

portsnap fetch update

and then executed portmaster to update all ports. This didn't work, however,
and portmaster stopped with the following error:

	===>>> The security/py-backports.ssl_match_hostname port has been
	       deleted: This functionality was backported to python 2.7.9
	===>>> Aborting update

Now I would like to delete security/py-backports.ssl_match_hostname but there
is no such port in the ports tree anymore.

Is there any other way to delete this port apart from checking out an old
version of the port tree that still has this port in it, then delete it, and
only then update?

Moritz