Set hard requirements for pip
Set hard requirements for pip

This change sets the requirement for pip to be pip>7,<8.
This is being done because the global pip wheel building
producing a built wheel for pip8 which causing downstream
breakage in the most current releases of master and liberty.

Change-Id: Iddcbba94c62dc87dac6fc25efb17b99ee8ec37d6
Closes-Bug: #1541193
Signed-off-by: Kevin Carter <ffb54fded2f22052678e45d78b58d223654eb6fa@rackspace.com>

cfarquhar/openstack-ansible,yanyao/openstack-ansible,yanyao/openstack-ansible,cfarquhar/openstack-ansible,BjoernT/os-ansible-deployment,openstack/openstack-ansible,yanyao/newton,mrda/openstack-ansible,weezer/openstack-ansible,os-cloud/os-ansible-deployment,BjoernT/openstack-ansible,openstack/openstack-ansible,Logan2211/openstack-ansible,stackforge/os-ansible-deployment,os-cloud/os-ansible-deployment,bunchc/openstack-ansible,major/openstack-ansible,weezer/openstack-ansible,yanyao/newton,robb-romans/openstack-ansible,major/os-ansible-deployment,robb-romans/openstack-ansible,mrda/openstack-ansible,Logan2211/openstack-ansible,major/os-ansible-deployment,BjoernT/openstack-ansible,bunchc/openstack-ansible,cloudnull/os-ansible-deployment,stackforge/os-ansible-deployment,major/openstack-ansible,mrda/openstack-ansible,BjoernT/os-ansible-deployment,BjoernT/os-ansible-deployment,mancdaz/openstack-ansible,cloudnull/os-ansible-deployment,mancdaz/openstack-ansible