3PAR: Narrow the focus of required client package

This restricts the range of the supported hp3parclient pypi
package to what will actually work with the 3PAR Block Storage
driver. This matches the versions specified in the
global-requirements.txt file as part of patch:
https://review.openstack.org/#/c/73727/1/global-requirements.txt

Change-Id: I30171f00a21687784050fcab9c5b5a43f8823b35
Merge "3PAR: Narrow the focus of required client package"