Update internal state when iface is removed.

Bug: 5433432
Change-Id: I7eb0ffe3ae07f42d5c47fe4082f490478c5099bf
diff --git a/services/java/com/android/server/NetworkManagementService.java b/services/java/com/android/server/NetworkManagementService.java
index b05705e..bcb1aa2 100644
--- a/services/java/com/android/server/NetworkManagementService.java
+++ b/services/java/com/android/server/NetworkManagementService.java
@@ -238,6 +238,11 @@
      * Notify our observers of an interface removal.
      */
     private void notifyInterfaceRemoved(String iface) {
+        // netd already clears out quota and alerts for removed ifaces; update
+        // our sanity-checking state.
+        mActiveAlertIfaces.remove(iface);
+        mActiveQuotaIfaces.remove(iface);
+
         for (INetworkManagementEventObserver obs : mObservers) {
             try {
                 obs.interfaceRemoved(iface);