Install SSL certificates

[erikng]

see gregneagle/relocatable-python#13

[erikng]

After trying to tackle this, I don't think it's currently possible. openssl is built by the python team and paths are hardcoded out.

requests library is not impacted by this issue, so maybe not the biggest deal?

[erikng]

This is now fixed! So long as no other mechanism is setting SSL_CERT_FILE, the file will now be used from certifi.