Projects: delete: delete all builds first

Deleting jobsets first would fail because buildmetrics has an FK
to the jobset. However, the jobset / project relationship is not
marked as CASCADE.

Deleting all the builds automatically cascades to delete
buildmetrics, so deleting the relevant builds first, then deleting
the jobset solves it.

src/lib/Hydra/Controller/Project.pm

@@ -78,8 +78,8 @@ sub project_DELETE {
     requireProjectOwner($c, $c->stash->{project});
 
     $c->model('DB')->schema->txn_do(sub {
-        $c->stash->{project}->jobsets->delete;
         $c->stash->{project}->builds->delete;
+        $c->stash->{project}->jobsets->delete;
         $c->stash->{project}->delete;
     });