Merge branch 'as/merge-attr-sleep' into maint

Fix for a racy false-positive test failure. * as/merge-attr-sleep: t6026: clarify the point of "kill $(cat sleep.pid)" t6026: ensure that long-running script really is Revert "t6026-merge-attr: don't fail if sleep exits early" Revert "t6026-merge-attr: ensure that the merge driver was called" t6026-merge-attr: ensure that the merge driver was called t6026-merge-attr: don't fail if sleep exits early