(no ticket) Reverted oi/0004 migration to autogenerated

The committed version had delete_index statements removed,
but they had to be deleted to workaround a bug in South
and it broke PostgreSQL.

See also:
https://bitbucket.org/andrewgodwin/south/pull-request/146/re-create-non-unique-indexes-in/diff

To temporarily use the fixed version, it was added to setup.py.
This should be removed once a fixed South version is released.

Change-Id: Icaccbeca473d9fc107954584ce5dcc8f44a5703a