Fix the location of the pidfile in the rpm and bump rpm to 2.4.1

The pidfile location pointed at by the default conf is not created by default so the process is currently broken.  This bug leads to issues where trying to kill the mongod via `service mongod stop` will kill all running mongod's on the box, not just the one that was started by the service.

I changed the location to be more in line with other default directories used and made sure that the directory now exists.

The bump to 2.4.1 was to ease the update of the hosted rpms.

https://jira.mongodb.org/browse/SERVER-7708