Update our boot receiver to schedule a message pull.

Previously we were starting a background service, which isn't allowed
for targetSdk 26. This will do the same thing but at a time decided by
the system.

src/org/thoughtcrime/securesms/service/BootReceiver.java

@@ -5,14 +5,13 @@ import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
 
+import org.thoughtcrime.securesms.ApplicationContext;
+import org.thoughtcrime.securesms.jobs.PushNotificationReceiveJob;
+
 public class BootReceiver extends BroadcastReceiver {
 
   @Override
   public void onReceive(Context context, Intent intent) {
-    if (intent != null && Intent.ACTION_BOOT_COMPLETED.equals(intent.getAction())) {
-      Intent messageRetrievalService = new Intent(context, MessageRetrievalService.class);
-      context.startService(messageRetrievalService);
-    }
+    ApplicationContext.getInstance(context).getJobManager().add(new PushNotificationReceiveJob(context));
   }
-
 }