Drop MANIFEST.in - it's not needed with PBR
Drop MANIFEST.in - it's not needed with PBR

This patch removes `MANIFEST.in` file as pbr generates a sensible
manifest from git files and some standard files and it removes
the need for an explicit `MANIFEST.in` file.

Change-Id: If35986a72aff015b25c9f4eccc0ab3a3e6997551

openstack/python-congressclient