Axis Animation (They did the CG cutscenes of Halo 4's Spartan Ops) posted this on their Facebook page:
This version of the Halo for Xbox One trailer shows 'Halo 5' at the end instead of just 'Halo' like in the E3 trailer: http://vimeo.com/73374802
Youtube: http://www.youtube.com/watch?v=-sIp4FRrN1k&feature=youtu.be
Credits to PentinantTangent for finding out.