Update upper bound of keystoneclient version.
Update upper bound of keystoneclient version.

This is the intermediate step so that we can update the the lower
bound of keystoneclient in openstack-requirements.

Change-Id: I1b73bfaafdf404634fc321b4e536f65b6dd65a3a

larsks/python-heatclient,metacloud/python-heatclient,citrix-openstack-build/python-heatclient,tcpcloud/python-heatclient,openstack/python-heatclient,citrix-openstack-build/python-heatclient,jasondunsmore/python-heatclient,ecerulm/python-heatclient,ecerulm/python-heatclient,rdo-management/python-heatclient,rdo-management/python-heatclient,varunarya10/python-heatclient,metacloud/python-heatclient,tcpcloud/python-heatclient,jasondunsmore/python-heatclient,varunarya10/python-heatclient,larsks/python-heatclient