signing-party: install missing pgp-{clean,fixkey}

There are two more useful perl scripts in caff's directory. They've been
missing until now, this commit adds them.

Closes Homebrew/homebrew#16746.

Signed-off-by: Charlie Sharpsteen <source@sharpsteen.net>

Formula/signing-party.rb

@@ -47,6 +47,8 @@ class SigningParty < Formula
       system "make"
       man1.install Dir['*.1']
       bin.install 'caff'
+      bin.install 'pgp-clean'
+      bin.install 'pgp-fixkey'
       (doc+'caff').install Dir['README*', 'caffrc.sample']
     end