EPEL pymongo rebase/rename

[Pádraig Brady]

Currently EPEL is at python-mongo-2.1 and I would like
to update to python-pymongo-2.4 to support OpenStack ceilometer at least.

According to http://docs.mongodb.org/manual/release-notes/ there doesn't
seem to be any obvious incompatibilities from the 2.1 development series.
I notice that Cyrus SASL is now used rather than GNU SASL, and
that the javascript engine has changed to V8.
Hopefully these won't cause an issue.

thanks,
Pádraig.