Remove explicit depend on distribute.
Remove explicit depend on distribute.

As per discussions with dstufft, explicit depends on distribute are
leading to pain - and will do more so with setuptools 0.7 out.
varunarya10/cliff,dtroyer/cliff,openstack/cliff,enzochiau/cliff,citrix-openstack-build/cliff,citrix-openstack-build/cliff,openstack/cliff,varunarya10/cliff,dtroyer/cliff,idjaw/cliff,enzochiau/cliff,idjaw/cliff