从14.04升级到16.04，virt-manager打不开
命令行使用virt-manager报错：
Traceback (most recent call last):
File "/usr/share/virt-manager/virt-manager", line 34, in <module>
from virtinst import util as util
File "/usr/share/virt-manager/virtinst/__init__.py", line 87, in <module>
from virtinst.distroinstaller import DistroInstaller
File "/usr/share/virt-manager/virtinst/distroinstaller.py", line 26, in <module>
from . import urlfetcher
File "/usr/share/virt-manager/virtinst/urlfetcher.py", line 27, in <module>
import requests
File "/usr/local/lib/python2.7/dist-packages/requests/__init__.py", line 53, in <module>
from .packages.urllib3.contrib import pyopenssl
File "/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/contrib/pyopenssl.py", line 70, in <module>
ssl.PROTOCOL_SSLv3: OpenSSL.SSL.SSLv3_METHOD,
AttributeError: 'module' object has no attribute 'PROTOCOL_SSLv3'

已解决
将/usr/local/lib/python2.7/dist-packages/requests/packages/urllib3/contrib/pyopenssl.pasty里的PROTOCOL_SSLv3改成PROTOCOL_SSLv23即可