am 64fcffd9: am f9ddfd23: am c7f2030f: am e022cb08: Merge "Don\'t attempt to stop the receive thread if we never started it." into mnc-dev

* commit '64fcffd901355a46318720d3ebaaa008d0abfe39':
  Don't attempt to stop the receive thread if we never started it.
diff --git a/services/net/java/android/net/dhcp/DhcpClient.java b/services/net/java/android/net/dhcp/DhcpClient.java
index 2d40291..9ee9cf4 100644
--- a/services/net/java/android/net/dhcp/DhcpClient.java
+++ b/services/net/java/android/net/dhcp/DhcpClient.java
@@ -603,7 +603,10 @@
         @Override
         public void exit() {
             cancelOneshotTimeout();
-            mReceiveThread.halt();  // Also closes sockets.
+            if (mReceiveThread != null) {
+                mReceiveThread.halt();  // Also closes sockets.
+                mReceiveThread = null;
+            }
             clearDhcpState();
         }