Move OpenPAM API extensions into <security/openpam.h> to avoid
namespace pollution for apps or modules that do not use them.
Sponsored by: DARPA, NAI Labs
git-svn-id: svn+ssh://svn.openpam.org/svn/openpam/trunk@39 185d5e19-27fe-0310-9dcf-9bff6b9f3609