Remove Babel requirement
Remove Babel requirement

Babel is not needed as requirement, remove it.

See also
http://lists.openstack.org/pipermail/openstack-discuss/2020-April/014227.html

Change-Id: Id6e22f7404db0fe36b3e3b3b5acec391b5aa65cf

openstack/python-ironicclient,openstack/python-ironicclient