Remove explicit distribute depend.
Remove explicit distribute depend.

Causes issues with the recent re-merge with setuptools. Advice from
upstream is to stop doing explicit depends.

Change-Id: Ie4c3eb42351f1ba5caa9b092db8f544d5a0cd7ba

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