bug#12289: 24.1; holidays.el does not account for Orthodox Christians using the Revised Julian calendar

[Carson Chittom]

holidays.el has

            (holiday-julian 12 25 "Eastern Orthodox Christmas")

In fact, my understanding is that this is only true for the Orthodox
Churches still using the Julian Calendar exclusively, most notably the
Russian Orthodox Church[1].  Several other Churches[2] use the Revised
Julian calendar, which is indistinguishable from the Gregorian until the
year 2800, for the fixed feasts of the ecclesiastical year.

However, even those on the Revised Julian still uses the (original)
Julian calendar for the calculation of Easter and the moveable feasts so
holiday-greek-orthodox-easter would still apply.

My source for this is http://orthodoxwiki.org/Revised_Julian_Calendar

[1] In addition to the Churches of Jerusalem, Serbia, Ukraine, and Georgia
[2] Constantinople, Antioch, Greece, Cyprus, Romania, Poland, Bulgaria,
and the Orthodox Church in America