decoding json only on 2xx success response bug 1007661
decoding json only on 2xx success response
bug 1007661

Change-Id: I9090c78bb9a19ae46d865fca80af0b3bf4257dc6

ntt-sic/python-keystoneclient,magic0704/python-keystoneclient,jamielennox/python-keystoneclient,darren-wang/ksc,ntt-sic/python-keystoneclient,ging/python-keystoneclient,darren-wang/ksc,citrix-openstack-build/python-keystoneclient,metacloud/python-keystoneclient,klmitch/python-keystoneclient,magic0704/python-keystoneclient,dolph/python-keystoneclient,alexpilotti/python-keystoneclient,metacloud/python-keystoneclient,jamielennox/python-keystoneclient,ging/python-keystoneclient,Mercador/python-keystoneclient,sdpp/python-keystoneclient,klmitch/python-keystoneclient,ntt-sic/python-keystoneclient,alexpilotti/python-keystoneclient,citrix-openstack-build/python-keystoneclient,dolph/python-keystoneclient,Mercador/python-keystoneclient,sdpp/python-keystoneclient,citrix-openstack-build/python-keystoneclient,jamielennox/python-keystoneclient