This also refactor the email_helper support spec to watch for multiple
emails being sent.

Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

So we can keep showing it to a user in his project page.

The helper creates a fork of a project with all provided attributes,
but skipping the creation of the repository on disk.

When no fork network exists for the source projects, we create a new
one with the correct source

In GitLab EE, a GitLab instance can be read-only (e.g. when it's a Geo
secondary node). But in GitLab CE it also might be useful to have the
"read-only" idea around. So port it back to GitLab CE.

Also having the principle of read-only in GitLab CE would hopefully
lead to less errors introduced, doing write operations when there
aren't allowed for read-only calls.

Closes gitlab-org/gitlab-ce#37534.

fetch_gcp_operation_service_spec. finalize_cluster_creation_service_spec. wait_for_cluster_creation_worker_spec.

Because of a change in GitLab 9.5.4 to prevent users from assuming control of
a repository already on disk, the import task broke. Imports would fail with
the message, "There is already a repository with that name on disk".

This change skips the validation when the import is done from the
command-line.

Closes #37682

Closes gitaly#601

Before this change, the MR counter in the sidebar would be wrong if an MR had
been merged since the last update, but not opened or closed, as merging did not
trigger a counter cache update.

MergeRequest#merge_jid should be cleaned up whenever we hit a known error on MergeService#execute. This way we can keep track if the MR is really "ongoing" or "stuck"