d6_user_role migration depends on d6_filter_format

Problem/Motivation

I ran into bizarre PHP errors and warnings while running the manifest file for testing the d6_upload migration. After several hours of poking at it, I realized that certain migrations were not being run in the correct order.

The d6_user_role migration is one of them -- it has an unmentioned dependency on the d6_filter_format migration. Why? Because d6_user_role invokes the filter_format_permission process plugin, which needs the d6_filter_format migration to have run. d6_filter_format, in turn, explicitly disallows stubbing of destination entities. So filter_format_permission ends up having no data to work with unless d6_user_role declares an explicit dependency on d6_filter_format.

Proposed Resolution

d6_user_role needs to declare an explicit dependency on d6_filter_format.

Remaining Tasks

RTBC and commit!

API Changes

None.

UI Changes

None.