Original commit message from CVS:
* gst/schedulers/gstoptimalscheduler.c: (add_to_group),
(remove_from_group), (normalize_group), (group_migrate_connected),
(gst_opt_scheduler_iterate):
* testsuite/schedulers/.cvsignore:
* testsuite/schedulers/Makefile.am:
* testsuite/schedulers/queue_link.c: (main):
Added testcase for schduler segfault.
Fix scheduler segfault when removing a decoupled
entry point as the last element from a group.
