3237 Draft deletion date should be displayed

https://code.google.com/p/otwarchive/issues/detail?id=3237

When saving: "Draft was successfully created. It will be deleted on 2014-04-22 01:34:25 -0400"

When viewing otherwise: "This work is a draft and has not been posted. The draft will be deleted on Tue 22 Apr 2014 01:34AM EDT"