Increase httplib._MAXHEADERS to 256.
Increase httplib._MAXHEADERS to 256.

By default Swift increase the number of max metadata count to 90
and extra header count to 32. That mean we can put 90 metadata to
Account/Container/Object by default, when user put 90 metadata to a
Account, the Account header count is close or more than 100. The
swift client unable to access Account and get an error likes,

('Connection aborted.', HTTPException('got more than 100 headers',))

So the default _MAXHEADERS(100) won't enough.

Change-Id: I5ffc4eb5d3e1ebc3dbdd7dc69376919ae3e1c5a8

sohonetlabs/python-swiftclient,jeseem/python-swiftclient,jeseem/python-swiftclient,openstack/python-swiftclient,sohonetlabs/python-swiftclient,VyacheslavHashov/python-swiftclient,ironsmile/python-swiftclient,VyacheslavHashov/python-swiftclient,ironsmile/python-swiftclient,openstack/python-swiftclient