Update changelog for Ember Data 2.4
Update changelog for Ember Data 2.4

rtablada/data,tarzan/data,rtablada/data,danmcclain/data,danmcclain/data,swarmbox/data,danmcclain/data,workmanw/data,ryanpatrickcook/data,courajs/data,tarzan/data,davidpett/data,wecc/data,ryanpatrickcook/data,davidpett/data,Eric-Guo/data,Eric-Guo/data,courajs/data,arenoir/data,HeroicEric/data,arenoir/data,ryanpatrickcook/data,Eric-Guo/data,nickiaconis/data,rtablada/data,vikram7/data,workmanw/data,workmanw/data,rtablada/data,vikram7/data,arenoir/data,wecc/data,courajs/data,wecc/data,HeroicEric/data,HeroicEric/data,workmanw/data,Eric-Guo/data,nickiaconis/data,HeroicEric/data,danmcclain/data,vikram7/data,courajs/data,davidpett/data,swarmbox/data,tarzan/data,swarmbox/data,davidpett/data,ryanpatrickcook/data,tarzan/data,nickiaconis/data,wecc/data,swarmbox/data,arenoir/data,nickiaconis/data,vikram7/data