Remove ligo_data_find from package distribution

The merge removes ligo_data_find from the repository. This executable has been deprecated for 2 years (see 5da1884e) so users have probably had enough time to move over to gw_data_find - this should push the rest of them.

I have attempted to remove references to ligo_data_find as well, namely in etup.py and the debian/ install lists, but also in something called VnPublish.py which almost certainly doesn't work any more anyway.

This doesn't remove the LDBD client libraries, but those should probably be removed as well.