#62 consider removing obsolete indexes after migration to 8.4

[Reece Hart]

In 8.3 with UTF-8, using an index for LIKE and regexp searches requires that it was created with text_pattern_ops. Unfortunately, t_p_o doesn't support the equality operator and therefore such indexes can't be used with equality predicates. This means that columns that might be searched by equality or with LIKE/regexp require two indexes: one with the default ops (text_ops, I think) and the other with text_pattern_ops.

t_p_o supports equality in 8.4, and thus obviates the default indexes on many tables. This ticket is a reminder to remove them.