Remove unused constant

The reference of the constant does not exist anymore.

Test: m
Change-Id: I592773bcb44632cc7b6ea4c17300a0bd6f4d3377
diff --git a/service/src/com/android/server/connectivity/AutomaticOnOffKeepaliveTracker.java b/service/src/com/android/server/connectivity/AutomaticOnOffKeepaliveTracker.java
index 9f9b496..6b7222a 100644
--- a/service/src/com/android/server/connectivity/AutomaticOnOffKeepaliveTracker.java
+++ b/service/src/com/android/server/connectivity/AutomaticOnOffKeepaliveTracker.java
@@ -88,7 +88,6 @@
 public class AutomaticOnOffKeepaliveTracker {
     private static final String TAG = "AutomaticOnOffKeepaliveTracker";
     private static final int[] ADDRESS_FAMILIES = new int[] {AF_INET6, AF_INET};
-    private static final String EXTRA_BINDER_TOKEN = "token";
     private static final long DEFAULT_TCP_POLLING_INTERVAL_MS = 120_000L;
     private static final long LOW_TCP_POLLING_INTERVAL_MS = 1_000L;
     private static final String AUTOMATIC_ON_OFF_KEEPALIVE_VERSION =