Delete stale bugs from elastic-recheck page

The following bugs show up with "No matches" in the
elastic recheck page, so let's mark them as
resolved in their respective yaml files by adding
a resolved_at attribute.

1252514 - Fixed by review
* https://review.openstack.org/57514

1251920 - Fixed by reviews
* https://review.openstack.org/58478

1251784 - Bunch of reviews are mentioned in the bug report,
not sure which one(s) specifically fixed the problem

1251512 - Duplicate of 1251920 which was fixed by review
* https://review.openstack.org/57509

1191960 - Fixed by review
* https://review.openstack.org/47632

1239637 - Fixed by review
* https://review.openstack.org/54850

Change-Id: I9c5d52aa510e79d4176740a00d0501ac4269d680
Merge "Delete stale bugs from elastic-recheck page"