refactor: remove unused proxy settings file
refactor: remove unused proxy settings file

This task file was orphaned in https://review.openstack.org/515397
and the functionality moved into tasks/main.yml so the task file
is no longer required.

Change-Id: I340df6b660f9d647eedd437f7ccce9060c3f5316

openstack/openstack-ansible-openstack_hosts,openstack/openstack-ansible-openstack_hosts