treewide: remove unnecessary use of fmt.Sprint

Change-Id: I619dcf56665365e09be27e7c58b8b3596715b8b4
Reviewed-on: https://review.monogon.dev/c/monogon/+/3016
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
Vouch-Run-CI: Tim Windelschmidt <tim@monogon.tech>
diff --git a/metropolis/pkg/event/etcd/etcd_test.go b/metropolis/pkg/event/etcd/etcd_test.go
index d4eb04f..45b5f98 100644
--- a/metropolis/pkg/event/etcd/etcd_test.go
+++ b/metropolis/pkg/event/etcd/etcd_test.go
@@ -833,8 +833,8 @@
 	res[g.Key] = g.Value
 
 	// These won't be part of the backlog.
-	tc.put(t, ks+"a", fmt.Sprintf("val-100"))
-	tc.put(t, ks+"b", fmt.Sprintf("val-101"))
+	tc.put(t, ks+"a", "val-100")
+	tc.put(t, ks+"b", "val-101")
 
 	// Retrieve the rest of the backlog until BacklogDone is returned.
 	nUpdates := 1