title: Repo sync error on macOS with _ssl.so image not found
body: <p>I've got my AOSP repo initialized after downloading a tar file from <a href="https://mirror.tuna.tsinghua.edu.cn/help/AOSP/" rel="nofollow noreferrer">mirro.tuna</a>, but I met the following error when I executed <code>repo sync</code>.</p>
  
  <pre><code>ERROR:root:code for hash md5 was not found.
  Traceback (most recent call last):
    File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 147, in &lt;module&gt;
      globals()[__func_name] = __get_hash(__func_name)
    File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/hashlib.py", line 97, in __get_builtin_constructor
      raise ValueError('unsupported hash type ' + name)
  ValueError: unsupported hash type sha512
  Traceback (most recent call last):
    File "/Volumes/Android/Source/aosp/.repo/repo/main.py", line 50, in &lt;module&gt;
      from git_config import init_ssh, close_ssh
    File "/Volumes/Android/Source/aosp/.repo/repo/git_config.py", line 24, in &lt;module&gt;
      import ssl
    File "/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/ssl.py", line 98, in &lt;module&gt;
      import _ssl             # if we can't import it, let the error propagate
  ImportError: dlopen(/usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/_ssl.so, 2): Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylib
    Referenced from: /usr/local/Cellar/python@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload/_ssl.so
    Reason: image not found
  </code></pre>