'module' object has on attribute 'connection'

run on ubuntu 3.19.0-23-generic #24~14.04.1-Ubuntu
docker-py version 1.8.1 and 1.8.0 failed, but version 1.7.0，1.7.2 is OK.

root@ide-staging-01:~# pip freeze | grep docker-py && python --version && docker version
docker-py==1.8.1
Python 2.7.6
Client:
 Version:      1.11.1
 API version:  1.23
 Go version:   go1.5.4
 Git commit:   5604cbe
 Built:        Tue Apr 26 23:30:23 2016
 OS/Arch:      linux/amd64

Server:
 Version:      1.11.1
 API version:  1.23
 Go version:   go1.5.4
 Git commit:   5604cbe
 Built:        Tue Apr 26 23:30:23 2016
 OS/Arch:      linux/amd64

root@ide-staging-01:~# uname -a
Linux ide-staging-01 3.19.0-23-generic #24~14.04.1-Ubuntu SMP Wed Jul 8 11:15:13 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
root@ide-staging-01:~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.2 LTS
Release:    14.04
Codename:   trusty

root@ide-staging-01:~# python
Python 2.7.6 (default, Jun 22 2015, 17:58:13)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from docker import Client
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/docker/__init__.py", line 20, in <module>
    from .client import Client, AutoVersionClient, from_env # flake8: noqa
  File "/usr/local/lib/python2.7/dist-packages/docker/client.py", line 25, in <module>
    from . import api
  File "/usr/local/lib/python2.7/dist-packages/docker/api/__init__.py", line 2, in <module>
    from .build import BuildApiMixin
  File "/usr/local/lib/python2.7/dist-packages/docker/api/build.py", line 9, in <module>
    from .. import utils
  File "/usr/local/lib/python2.7/dist-packages/docker/utils/__init__.py", line 1, in <module>
    from .utils import (
  File "/usr/local/lib/python2.7/dist-packages/docker/utils/utils.py", line 33, in <module>
    from .. import tls
  File "/usr/local/lib/python2.7/dist-packages/docker/tls.py", line 5, in <module>
    from .ssladapter import ssladapter
  File "/usr/local/lib/python2.7/dist-packages/docker/ssladapter/__init__.py", line 1, in <module>
    from .ssladapter import SSLAdapter # flake8: noqa
  File "/usr/local/lib/python2.7/dist-packages/docker/ssladapter/ssladapter.py", line 22, in <module>
    urllib3.connection.match_hostname = match_hostname
AttributeError: 'module' object has no attribute 'connection'
>>>

Start with docker/ssladapter/ssladapter.py and follow the import chain shown in the traceback through docker/tls.py and docker/utils/utils.py. Reproduce the failure with the reported Python and docker-py versions, then verify that from docker import Client imports successfully without the AttributeError.