Prior to this change, the migration touched the disk path. This has been
removed.

Further, I believe it also fixes a bug. It seems that GitLab Shell
checks if the root path exists, when the path is duplicated. For
example, if the shard is located at /home/git, it did check if
`/home/git/home/git` existed.

This old migration used Rugged to find a commit, while Gitaly is the
prefered way now. By migrating this to Gitaly, Gitaly is now a required
running component for this migration.

Part of https://gitlab.com/gitlab-org/gitaly/issues/1106

This reverts commit 4d9a3f42f1fd3be21555e19872b7121cca65015e, reversing
changes made to ecf9c145f6e4d170cd059df88743393d9e63c489.

Port of Todos for epics

See merge request gitlab-org/gitlab-ce!19908

For reasons unknown, the logs of a web hook were paginated in memory.
This would result in the "Edit" page of a web hook timing out once it
has more than a few thousand log entries.

This commit makes the following changes:

1. We use LIMIT/OFFSET to paginate the data, instead of doing this in
   memory.

2. We limit the logs to the last two days, just like the documentation
   says (instead of retrieving everything).

3. We change the indexes on "web_hook_logs" so the query to get the data
   can perform a backwards index scan, without the need for a Filter.

These changes combined ensure that Projects::HooksController#edit no
longer times out.

* Group filtering now includes also issues/MRs from
subgroups/subprojects
* fixed due_date
* Also DRYed todo controller specs