bug 1221203 Fixes Wadl file and adds more description to role.

Change-Id: I216508c719867ed96fd1b3278581fe3de35b5dfa
Merge "bug 1221203 Fixes Wadl file and adds more description to role."
Change instances of OS-FILTER to OS-EP-FILTER

Mark Miller reported this on -dev mailing. There are some instances of
OS-FILTER being used in the endpoint filtering documentation.
This patch will change those instances to OS-EP-FILTER.

Change-Id: I5bd1986ee36a3fadc25d289cea4819c70c3c3e0e