7089: same bug was pasted into BirthdayReport!

Moved the utility function gregorian to gen.lib.date,
and use it like in WebCal.

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/maintenance/gramps34@23211 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
7089: copy fix from BirthdayReport to Calendar

Evil cut and paste of a bug fix,
following the evil cut and paste of the original code...

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/branches/maintenance/gramps34@23212 4ae1f11a-8b86-4847-b8af-ab372f36d1fd