This adjusts the partial condition for an index. The index is intended
to be used when counting active users with `ghost IS NOT TRUE AND
bot_type IS NULL`.

With the current index, this wasn't working as the partial condition
didn't match the query: `ghost <> TRUE` is not semantically equivalent
to `ghost IS NOT TRUE` (null semantics).

The reason we add an index particularly intended for EE is that the EE
query is going to have the additional part `AND bot_type IS NULL`
whereas the CE query doesn't. Logically, it'd be enough to have an index
for `ghost IS NOT TRUE`. However, on GitLab.com, the query planner makes
poor choices when the additional `AND bot_type IS NULL` part is present:
It goes for the index on `bot_type` and doesn't use the partial index.

Note the existing index isn't being used at all according to GitLab.com
index statistics. Hence we can first remove it and don't have to worry
about the window of time without an index.

Relates to https://gitlab.com/gitlab-org/gitlab-ce/issues/66770

Rename epic column state to state_id to be consistent with
issues and merge requests

Use image proxy to mitigate stealing ip addresses

Closes #2812

See merge request gitlab/gitlabhq!2926

Require a captcha after unique failed logins from the same IP

See merge request gitlab/gitlabhq!3270

Introduce JobActivity limit for alive jobs

Closes gitlab-ee#376

See merge request gitlab/gitlabhq!3339

Now we have cluster_id, state index, we don't the cluster_id index as
well.

For Environment.deployed_to_cluster

Persists if a board list is collapsed for each user.