libkface and new opencv

[Steve Wills]

Hi,

I've been working on the update of graphics/opencv to the latest version 
(3.4.1) and have run into an issue with the update to opencv breaking 
libkface. See:

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=210505

Looking at libkface, I see that it doesn't seem to be maintained any 
more. It seems like digikam stopped using it, and that was the only 
thing using it. I also noticed Fedora (and possibly others) have stopped 
packaging it because of this same issue and the fact that it doesn't 
seem to be maintained any more.

The patch for opencv changes digicam to use opencv directly rather than 
using libkface, but I'm not familiar enough with digicam to be confident 
that this provides the same functionality.

I would like input from some kde at FreeBSD.org person to figure out if 
this change is OK and we can deprecate libkface or if we need to figure 
out how to fix libkface.

Thanks,
Steve