python-urllib3 1.25.6 uploaded to experimental (closes CVE-2019-11236) but fails build tests

[Drew Parsons]

Hi Daniele, just letting you know I uploaded python-urllib3 1.25.6 to 
experimental.

I was having some SSL trouble connecting to https://pub.orcid.org.  The 
error trace cited urllib3/contrib/pyopenssl.py, so I downloaded and 
installed python-urllib3 1.25.6 to see if updates to default SSL/TLS 
versions made any difference.  It didn't fix my problem, but since I had 
the package update ready I figured I might as well present it to 
experimental.

The new version fixes CVE-2019-11236 (Bug#927172).  As far as I can tell 
it also fixes CVE-2019-11324 (Bug#927412), but I figured it's best to 
let you review that.

Th package build was successful on my system but gives build-time errors 
in chroot (on buildd).  I'm not sure why that's failing.

Drew