With hashed storage enabled, we would fail to transfer a project to another
namespace because the provided paths were wrong. Instead, we should not
attempt to move paths at all.

Closes gitlab-org/gitlab-ee#4056

Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

This ensures that project authorizations are refreshed when moving a
project from one namespace to another. When doing so the permissions for
all users of both the old and new namespaces are refreshed.

See #26194 for more information.

- Move UploadsTransfer to ProjectTransfer and inherit from this to UploadsTransfer and PagesTransfer

Flushing the events cache worked by updating a recent number of rows in
the "events" table. This has the result that on PostgreSQL a lot of dead
tuples are produced on a regular basis. This in turn means that
PostgreSQL will spend considerable amounts of time vacuuming this table.
This in turn can lead to an increase of database load.

For GitLab.com we measured the impact of not using events caching and
found no measurable increase in response timings. Meanwhile not flushing
the events cache lead to the "events" table having no more dead tuples
as now rows are only inserted into this table.

As a result of this we are hereby removing events caching as it does not
appear to help and only increases database load.

For more information see the following comment:
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/6578#note_18864037

This reverts commit 3e991230.

# Conflicts:
#	app/models/project.rb

Closes gitlab-org/gitlab-ee#506

This reverts commit 5daf44b7, reversing
changes made to 2f706fbd.

This reverts commit 957e849f, reversing
changes made to 6b9dbe9f.
Signed-off-by: NDmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Make the following changes to deal with new behavior in Rails 4.1.2:

* Use nested resources to avoid slashes in arguments to path helpers.