Delete  MANIFEST.in in os-brick
Delete  MANIFEST.in in os-brick

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: If04e62b7def7553e919fc8de8003c9dcc2bb2341

openstack/os-brick,openstack/os-brick