Remove som GYP annotations, remove unused manifest.

build/android/pylib/device/commands/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/rules.gni")
 
 group("commands") {
   data_deps = [
     ":chromium_commands",
   ]
 }
 
-# GYP: //build/android/pylib/device/commands/commands.gyp:chromium_commands
 android_library("chromium_commands") {
   java_files = [ "java/src/org/chromium/android/commands/unzip/Unzip.java" ]
   dex_path = "$root_build_dir/lib.java/chromium_commands.dex.jar"
 }