graphics/gimp-manual-html/Makefile contains dead link

[Andre Goeree]

Hello porters,

The link in the Makefile of graphics/gimp-manual-html seems to be dead. 

Googling for the files gave me some links that work:
http://kefk.net/Open_Source/FS/GIMP/Download/GUM/
http://ftp.nluug.nl/ftp/graphics/gimp/manual/
http://csociety-ftp.ecn.purdue.edu/pub/gimp/manual/
ftp://ftp.pl.debian.org/mirror/ftp.gimp.org/pub/manual/
http://ftp.ussg.iu.edu/gimp/manual/

Could you please update the links in the Makefile.
Thanks in advance,

Andre