Update TeleService for guava 27.1

Futures.addCallback now requires an Executor argument.

Bug: 130306229
Test: m checkbuild
Change-Id: I7c4045662eb9b8e12c46e953f8535e0c939cb493
diff --git a/src/com/android/phone/NetworkScanHelper.java b/src/com/android/phone/NetworkScanHelper.java
index a21f547..fcfbf22 100644
--- a/src/com/android/phone/NetworkScanHelper.java
+++ b/src/com/android/phone/NetworkScanHelper.java
@@ -31,6 +31,7 @@
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.MoreExecutors;
 import com.google.common.util.concurrent.SettableFuture;
 
 import java.lang.annotation.Retention;
@@ -180,7 +181,7 @@
                     int errCode = Integer.parseInt(t.getMessage());
                     onError(errCode);
                 }
-            });
+            }, MoreExecutors.directExecutor());
             mExecutor.execute(new NetworkScanSyncTask(
                     mTelephonyManager, (SettableFuture) mNetworkScanFuture));
         } else if (type == NETWORK_SCAN_TYPE_INCREMENTAL_RESULTS) {