routing: penalize node-level failures harder

Previously we only penalized the outgoing connections of a failing node.
This turned out not to be sufficient, because the next route sometimes
went into the same failing node again to try a different outgoing
connection that wasn't yet known to mission control and therefore not
penalized before.

routing/missioncontrol.go

@@ -333,18 +333,18 @@ func (m *MissionControl) setLastPairResult(fromNode, toNode route.Vertex,
 	nodePairs[toNode] = current
 }
 
-// setAllFail stores a fail result for all known connection of the given node.
-func (m *MissionControl) setAllFail(fromNode route.Vertex,
+// setAllFail stores a fail result for all known connections to and from the
+// given node.
+func (m *MissionControl) setAllFail(node route.Vertex,
 	timestamp time.Time) {
 
-	nodePairs, ok := m.lastPairResult[fromNode]
-	if !ok {
-		return
-	}
-
-	for connection := range nodePairs {
-		nodePairs[connection] = TimedPairResult{
-			FailTime: timestamp,
+	for fromNode, nodePairs := range m.lastPairResult {
+		for toNode := range nodePairs {
+			if fromNode == node || toNode == node {
+				nodePairs[toNode] = TimedPairResult{
+					FailTime: timestamp,
+				}
+			}
 		}
 	}
 }