Error Related to Delivery Type.

Open source community noticed a change in delivery type is causing "whoops error" when trying to delete files. 
Discussion: http://vanillaforums.org/discussion/comment/216330/#Comment_216330
Related to delivery type change here: https://github.com/vanilla/vanilla/commit/a69fa4048bd299d3248f0ff2897cde5e0ea93065
Merge pull request #139 from adriansonline/patch-1

Error Related to Delivery Type.