Remove the 'MANIFEST.in'
Remove the 'MANIFEST.in'

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: I12b6c279dcc6d56d0bd4b48c5d5c3edf33bab5f1

stackforge/solum-dashboard,stackforge/solum-dashboard,openstack/solum-dashboard,openstack/solum-dashboard