Improved the scenario risk QA tests
Removed the ScenarioGetter special case
Removed the fake dependency on task_no from the hazard_getters
Added a forgotten migration
Simplified the GMF getters
Merged from master
Merge branch 'master' into fix-ordering-hazard-getters
Fixed the numbers in scenario/case_2
Added a docstring
Merge pull request #1506 from gem/fix-ordering-hazard-getters

Replaced the ScenarioGetter with the GroundMotionFieldGetter