Why did apt-get remove my equivs-made package to install gnupg?

[Adam Funk <a24061@yahoo.com>]

I compiled GnuPG myself and installed it in /usr/local/.  To satisfy
dependencies I created the following control file

Package: gnupg-af
Provides: gnupg
Conflicts: gnupg
Description: GnuPG compiled by AF.
 GnuPG compiled by AF

and made a package file and installed it.  A few days ago, while I was
upgrading some KDE packages, apt-get required removing that package
and installing the official gnupg package.  Why?

I'd like to remove the official package and keep using my own
compilation only, but `dpkg -i gnupg-af_1.0_all.deb` wants to remove
gnupg and the packages that depend on it, even thought gnupg-af
"Provides: gnupg".