requirements: bump up python-openstackclient

requirements: bump up python-openstackclient

please note, some packages not related to python-openstackclient are
also updated. the reason is that, because before this change, all
packages are pin'ed to a certain version, but after this change
only the direct dependencies are pin'ed using requirements.txt,
so, if any of the direct dependencies does not pin its own dependencies
to a certain version, pip-compile will pick the latest available version
from pypi to fulfill the requirement, and generated requirements.txt
accordingly.

Signed-off-by: Kefu Chai <kchai@redhat.com>