ignore_ssl_certs failure on Python 2.7

[adiroiban]

Many thanks for this nice tool!

A quick fix for python 2.7

-        context = ssl.SSLContext()
+        context = ssl.SSLContext(ssl.PROTOCOL_TLS)

in py2.7 you need to specify the SSL protocol

Error details for a run like nodeenv --ignore_ssl_certs --prebuilt build-server/nodeenv

  File "/home/adi/chevah/server/build-server/lib/python2.7/site-packages/nodeenv.py", line 1068, in main
    opt.node = get_last_stable_node_version()
  File "/home/adi/chevah/server/build-server/lib/python2.7/site-packages/nodeenv.py", line 1002, in get_last_stable_node_version
    return _get_versions_json()[0]['version'].lstrip('v')
  File "/home/adi/chevah/server/build-server/lib/python2.7/site-packages/nodeenv.py", line 978, in _get_versions_json
    response = urlopen('%s/index.json' % src_base_url)
  File "/home/adi/chevah/server/build-server/lib/python2.7/site-packages/nodeenv.py", line 603, in urlopen
    context = ssl.SSLContext()
TypeError: __new__() takes at least 2 arguments (1 given)

nodeenv/nodeenv.py

Line 608 in 2676823

context = ssl.SSLContext()

[ekalinin]

Thanks for the report!