Drop python2.5 suport in ironicclient.common.http
Drop python2.5 suport in ironicclient.common.http

json and ssl modules were added in python 2.6 (see [1] [2]), so we should
suppose, that these module always available in python standard library.

[1] http://docs.python.org/2/library/ssl.html
[2] http://docs.python.org/2/library/json.html

Change-Id: I37d0cf7240180b0c2dbed26cfd9b264952ab822e

NaohiroTamura/python-ironicclient,ramineni/myclient,rdo-management/python-ironicclient,NaohiroTamura/python-ironicclient,CiscoUcs/UCS-python-ironicclinet,bcrochet/python-ironicclient,JioCloud/python-ironicclient,openstack/python-ironicclient,varunarya10/python-ironicclient,redhat-openstack/python-ironicclient,openstack/python-ironicclient