treewide: Fix ENUM_VALUE_PREFIX rule exception

Change-Id: Ibc2fd66711f6aa347e88e2379c12db1898373700
Reviewed-on: https://review.monogon.dev/c/monogon/+/3804
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/metropolis/node/core/update/update.go b/metropolis/node/core/update/update.go
index b4183ad..ef302d1 100644
--- a/metropolis/node/core/update/update.go
+++ b/metropolis/node/core/update/update.go
@@ -199,9 +199,9 @@
 		return fmt.Errorf("bad A/B state: %w", err)
 	}
 	slotToLoad := Slot(state.ActiveSlot)
-	if state.NextSlot != abloaderpb.Slot_NONE {
+	if state.NextSlot != abloaderpb.Slot_SLOT_NONE {
 		slotToLoad = Slot(state.NextSlot)
-		state.NextSlot = abloaderpb.Slot_NONE
+		state.NextSlot = abloaderpb.Slot_SLOT_NONE
 		err = s.setABState(state)
 		if err != nil {
 			return fmt.Errorf("while updating A/B state: %w", err)