Use Hash#each_with_object to manipulate job hashes.

Revert "Add Build seed specs"

This reverts commit 03bc722e.

Revert "Add build specs"

This reverts commit c2d49565.

Revert "Refactor parallelization implementation"

This reverts commit 72430483.

Revert "Implement POC for job parallelization"

This reverts commit 44b740f9.

* Move the variables to ::Ci::Build#predefined_variables
* Tweak pipeline build seed implementation

remove duplicate section for enable at project level

See merge request gitlab-org/gitlab-ee!8112

CE upstream - 2018-10-26 20:21 UTC

See merge request gitlab-org/gitlab-ee!8115

Explain how to use custom setup cmd

See merge request gitlab-org/gitlab-ee!7680

# Conflicts:
#	doc/README.md
#	lib/gitlab/checks/change_access.rb

[ci skip]

CE upstream - 2018-10-26 16:28 UTC

Closes gitlab-qa#59

See merge request gitlab-org/gitlab-ee!8111

User not defined in PostReceive#process_project_changes

Closes #51335

See merge request gitlab-org/gitlab-ce!22519

Adds tracing messages for slow git pushes

See merge request gitlab-org/gitlab-ee!8041

Adds trace of each access check when git push times out

Closes #42790

See merge request gitlab-org/gitlab-ce!22265

Upgrade Prometheus to 2.4.3 and Alertmanager to 0.15.2

See merge request gitlab-org/gitlab-ce!22600