
Without this version, markers will fail to install in a growing number of projects. Change global-requirements to prevent pip -r requirements.txt; pip install . failing with an already installed and too old for setup_requires pbr. Change update.py to signal to setuptools the minimum version required, giving clearer error messages in the case of downgrades during devstack. Change-Id: I074274b470a7a4f2c95211677b135038ab2c942c