[utils] make_HTTPS_handler:  Use ssl.create_default_context in Python 2.7.9

The new features in the ssl module have been backported from 3.4, see https://docs.python.org/dev/whatsnew/2.7.html#pep-466-network-security-enhancements-for-python-2-7
[utils] make_HTTPS_handler: Remove try/except block that would always raise an exception

This code is only run for Python < 3.4, where context.load_default_certs doesn't exist