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
Run unittest with python 3.3

Synchronized common gettextutils module from oslo due
to get possibility to run tests in py33 tox environment

Change-Id: I5970ce41edeab3fe5ec3fecf606f5f5d2a54a7b0
Merge "Drop python2.5 suport in ironicclient.common.http"
Merge "Run unittest with python 3.3"