edx/edx-platform — pull request #4947 by tymofij (2014-08-22 19:25:17+00:00)
Title: Unflag Group Configurations; Render only existing children in staff view of split_test.

This fixes

* [BLD-1224](https://openedx.atlassian.net/browse/BLD-1224) Error split test rendering in LMS
* [BLD-1229](https://openedx.atlassian.net/browse/BLD-1229) Do not hide Group Configuration editor behind feature flag

Root cause for BLD-1224 is that group_id_to_child contains deleted groups.
Other solution is to clean group_id_to_child of split_test when group was deleted from group configuration page. But this will affect publishing. So this solution was implemented but skipped.

review granted: @cahrens

Also this provides fix for https://openedx.atlassian.net/browse/BLD-1249.