Move denyhosts to boneyard

This formula does not configure the software correctly.
In addition, MacPorts blacklists it from newer versions of OS X.

See:
https://github.com/mxcl/homebrew/issues/21484
https://trac.macports.org/browser/trunk/dports/security/denyhosts/Portfile

Closes Homebrew/homebrew#21484.

Library/Homebrew/tap_migrations.rb

 TAP_MIGRATIONS = {
   'octave' => 'homebrew/science',
   'grads' => 'homebrew/binary',
+  'denyhosts' => 'homebrew/boneyard'
 }