Remove odd package derivations with mismatched systems

This follows on from 79993bfaef, disassociating
the relevant derivations from the revisions.

sqitch/deploy/remove_odd_package_derivations.sql

@@ -0,0 +1,23 @@
+-- Deploy guix-data-service:remove_odd_package_derivations to pg
+
+BEGIN;
+
+DELETE FROM guix_revision_package_derivations
+WHERE package_derivation_id IN (
+  SELECT package_derivations.id
+  FROM package_derivations
+  INNER JOIN derivations
+    ON package_derivations.derivation_id = derivations.id
+  WHERE package_derivations.system != derivations.system
+);
+
+DELETE FROM package_derivations
+WHERE id IN (
+  SELECT package_derivations.id
+  FROM package_derivations
+  INNER JOIN derivations
+    ON package_derivations.derivation_id = derivations.id
+  WHERE package_derivations.system != derivations.system
+);
+
+COMMIT;

sqitch/revert/remove_odd_package_derivations.sql

@@ -0,0 +1,7 @@
+-- Revert guix-data-service:remove_odd_package_derivations from pg
+
+BEGIN;
+
+-- XXX Add DDLs here.
+
+COMMIT;

sqitch/sqitch.plan

@@ -56,3 +56,4 @@ guix_revision_system_test_derivations_add_system 2020-03-19T21:30:33Z Christophe
 drop_package_versions_by_guix_revision_range 2020-03-24T20:40:38Z Christopher Baines <mail@cbaines.net> # Drop package_versions_by_guix_revision_range
 create_narinfo_fetch_records_index 2020-03-25T19:07:28Z Christopher Baines <mail@cbaines.net> # Create an index on narinfo_fetch_records
 load_new_guix_revision_jobs_make_commits_unique 2020-03-27T21:38:42Z Christopher Baines <mail@cbaines.net> # Make load_new_guix_revision_jobs commits unique
+remove_odd_package_derivations 2020-04-24T20:36:06Z Christopher Baines <mail@cbaines.net> # Remove odd package derivations

sqitch/verify/remove_odd_package_derivations.sql

@@ -0,0 +1,7 @@
+-- Verify guix-data-service:remove_odd_package_derivations on pg
+
+BEGIN;
+
+-- XXX Add verifications here.
+
+ROLLBACK;