Notify SipSessions before closing SIP stack.

Bug: 3116480
Change-Id: I748d63382ade250aed27ccb09ea68c76a433fd27
diff --git a/voip/java/com/android/server/sip/SipSessionGroup.java b/voip/java/com/android/server/sip/SipSessionGroup.java
index 50ce7dc..2fbaee2 100644
--- a/voip/java/com/android/server/sip/SipSessionGroup.java
+++ b/voip/java/com/android/server/sip/SipSessionGroup.java
@@ -190,6 +190,7 @@
 
     public synchronized void close() {
         Log.d(TAG, " close stack for " + mLocalProfile.getUriString());
+        onConnectivityChanged();
         mSessionMap.clear();
         closeToNotReceiveCalls();
         if (mSipStack != null) {