CIVICRM-754: Custom file upload field not showing up when Viewing Activity from Case Report

Steps to reproduce the bug:

1. Create two custom fields, both of type file (Attachments) that use for Activities
2. Create new case and upload files in those couple of fields.
3. Open("View") the Last activity of type "Open Case"
4. In the recent builds you can see the files, but two files are listed under both custom fields. Which is not correct, we should only see single file in front of each custom field. In previous builds the values doesn't show up at all.
5. Click on edit activity icon, you can see both the files are attached separably on each custom field.