Merge branch 'default-sortable-tolerance-option' into 'master'

Added fallback tolerance to epic tree drag

See merge request gitlab-org/gitlab!26920

app/assets/javascripts/boards/mixins/sortable_default_options.js

@@ -26,7 +26,6 @@ export function getBoardSortableDefaultOptions(obj) {
     scrollSpeed: 20,
     onStart: sortableStart,
     onEnd: sortableEnd,
-    fallbackTolerance: 1,
   });
 
   Object.keys(obj).forEach(key => {

ee/app/assets/javascripts/sortable/sortable_config.js

@@ -4,4 +4,5 @@ export default {
   fallbackClass: 'is-dragging',
   fallbackOnBody: true,
   ghostClass: 'is-ghost',
+  fallbackTolerance: 1,
 };