title: buildozer android NDK not downloading Ubuntu
body: <p>I'am using the OS Ubuntu 16.04 LTS. I have installed the buildozer in the python2 and python3.The android sdk is installed but the buildozer is showing error while downloading android NDK.Please do help me to solve this issue.
  Following is the <strong>Error.</strong></p>
  
  <pre><code>  # Downloading http://dl.google.com/android/repository/android-ndk-r9c-linux-x86_64.tar.bz2
  Traceback (most recent call last):
    File "/home/fadii/.local/bin/buildozer", line 11, in &lt;module&gt;
      sys.exit(main())
    File "/usr/local/lib/python3.5/dist-packages/buildozer-0.33.dev0-py3.5.egg/buildozer/scripts/client.py", line 13, in main
      Buildozer().run_command(sys.argv[1:])
    File "/usr/local/lib/python3.5/dist-packages/buildozer-0.33.dev0-py3.5.egg/buildozer/__init__.py", line 1026, in run_command
      self.target.run_commands(args)
    File "/usr/local/lib/python3.5/dist-packages/buildozer-0.33.dev0-py3.5.egg/buildozer/target.py", line 91, in run_commands
      func(args)
    File "/usr/local/lib/python3.5/dist-packages/buildozer-0.33.dev0-py3.5.egg/buildozer/target.py", line 101, in cmd_debug
      self.buildozer.prepare_for_build()
    File "/usr/local/lib/python3.5/dist-packages/buildozer-0.33.dev0-py3.5.egg/buildozer/__init__.py", line 175, in prepare_for_build
      self.target.install_platform()
    File "/usr/local/lib/python3.5/dist-packages/buildozer-0.33.dev0-py3.5.egg/buildozer/targets/android.py", line 499, in install_platform
      self._install_android_ndk()
    File "/usr/local/lib/python3.5/dist-packages/buildozer-0.33.dev0-py3.5.egg/buildozer/targets/android.py", line 309, in _install_android_ndk
      cwd=self.buildozer.global_platform_dir)
    File "/usr/local/lib/python3.5/dist-packages/buildozer-0.33.dev0-py3.5.egg/buildozer/__init__.py", line 671, in download
      urlretrieve(url, filename, report_hook)
    File "/usr/lib/python3.5/urllib/request.py", line 1760, in retrieve
      block = fp.read(bs)
    File "/usr/lib/python3.5/tempfile.py", line 622, in func_wrapper
      return func(*args, **kwargs)
  </code></pre>