treewide: add missing error handling

Change-Id: I55ccf3ff490b58f6af93e665c668428acddc8d65
Reviewed-on: https://review.monogon.dev/c/monogon/+/3019
Vouch-Run-CI: Tim Windelschmidt <tim@monogon.tech>
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/cloud/bmaas/bmdb/migrations_test.go b/cloud/bmaas/bmdb/migrations_test.go
index 65eef7f..1a70655 100644
--- a/cloud/bmaas/bmdb/migrations_test.go
+++ b/cloud/bmaas/bmdb/migrations_test.go
@@ -135,6 +135,9 @@
 	rows, err := conn.db.Query(`
 		SELECT machine_id, process, until, cause FROM work_backoff
 	`)
+	if err != nil {
+		t.Fatalf("Could not fetch old-style backoff data: %v", err)
+	}
 	for rows.Next() {
 		var mid, process, until, cause string
 		if err := rows.Scan(&mid, &process, &until, &cause); err != nil {