Fix generate_useful_gather_paths for parallel unsafe pathkeys

When Who What
2020-12-22 01:14:38 Tomas Vondra (fuzzycz) Closed in commitfest 2021-01 with status: Committed
2020-12-22 01:14:38 Tomas Vondra (fuzzycz) Changed committer to fuzzycz
2020-12-01 00:10:27 James Coleman (jcole1989) Changed reviewers to Tomas Vondra (fuzzycz)
2020-12-01 00:10:26 James Coleman (jcole1989) Changed authors to James Coleman (jcole1989)
2020-12-01 00:10:13 James Coleman (jcole1989) Attached mail thread CAAaqYe8cK3g5CfLC4w7bs=hC0mSksZC=H5M8LSchj5e5OxpTAg@mail.gmail.com
2020-12-01 00:10:13 James Coleman (jcole1989) Created patch record