The cadence of Fedora and OpenStack releases are in sync, and so we have
- Fedora 16 = Diablo
- Fedora 19 = Grizzly
- Fedora 20 = Havana
- Fedora 21 = Icehouse
- Fedora 22 = Juno
For other combinations please see the RDO community site which provides RPMs for Fedora and RHEL (derivatives).
There you can get the current OpenStack development release RPMs for the current Fedora stable release (for example Icehouse RPMs for Fedora 20).