Fix MR 500 when viewing the MR page

Fixes #2712 

See merge request !2167

Explicitly require Nokogiri 1.6.7.1 due to security issue

```
Name: nokogiri
Version: 1.6.7
Advisory: CVE-2015-5312
Criticality: High
URL: https://groups.google.com/forum/#!topic/ruby-security-ann/aSbgDiwb24s
Title: Nokogiri gem contains several vulnerabilities in libxml2
Solution: upgrade to >= 1.6.7.1
```

See merge request !2154

Also, make it not fail.

This is required since we parse URI later and remove the credentials

Also adds a spec for MergeRequestHelper to avoid having a regression
later on.

[ci skip]

Fixed wrong URL to "up for grabs" issue filter

[ci skip]

See merge request !2162

Allow admin to create new user identities

Fixes #2442 

See merge request !2077

Fix issue related cross-project MRs

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/4188

See merge request !2163

Allow account unlock via email

We see a lot of users get confused about what it means when your account gets
locked. Many try to reset their password and are still faced with a lockout.
With this change, users receive an email that allows them to unlock their
account immediately. The previous behavior where the account is auto-unlocked
after a time also still works.

See merge request !2049

Show git version on admin page

Before
![git-version-beore](/uploads/57444ad42220c9dfe8f187b8e399227f/git-version-beore.png)

After
![git-version-after](/uploads/cc1b52ae1a251c2c46d9626c040726ab/git-version-after.png)

gitlab-org/gitlab-ce#4077




See merge request !2101

Fix build coverage regex matching to allow captures.

Fixes #2644 

/cc @DouweM 

See merge request !2138

Backport JIRA service

Fixes #3839 

Move EE JIRA functionality back to CE.

- [x] Make it function in manual testing
- [x] Migrate JIRA-specific tests
- [x] Tests pass
- [x] Migrate documentation
- [x] Rollback to previous CE JIRA integration locally, activate on a project then try to migrate db and see if integration still works.
- [x] Final EE search for JIRA references

See merge request !2146

Added a spec for regex captures as well.

Fixes #2644

Remove CI_BUILD_BEFORE_SHA from CI documentation

As pointed in #3210, the environment variable isn't usable any more.

See merge request !2118

Clarify Windows shell executor artifact upload support

@ayufan noted that the runner does not support artifact upload for Windows shell executor. This adds a note so users aren't confused.

See merge request !2142

Don't create CI status for refs that doesn't have .gitlab-ci.yml, even if the builds are enabled

Fixes #3827 
Fixes #4157

/cc @grzesiek @dblessing 

See merge request !2139

Do not display project group/name when issue and MR are in same project

I noticed that things seem a bit cluttered for related merge requests
when displaying the group/project name for every item, even when it's
in the same project.

For merge requests that are in the same project as the issue we probably
don't need to display the 'in group / name' bit.

See merge request !2141

Name: nokogiri
Version: 1.6.7
Advisory: CVE-2015-5312
Criticality: High
URL:
https://groups.google.com/forum/#!topic/ruby-security-ann/aSbgDiwb24s
Title: Nokogiri gem contains several vulnerabilities in libxml2
Solution: upgrade to >= 1.6.7.1

Bump Rack Attack to v4.3.1 for security fix

https://github.com/kickstarter/rack-attack/releases/tag/v4.3.1

See merge request !2153

https://github.com/kickstarter/rack-attack/releases/tag/v4.3.1

Remove extra spaces after branchname

See merge request !2152

Fix merge-request-reopen button title

Closes #4069

See merge request !2147

Add new branch and tag action to tree dropdown

Right now, creating a branch or tag is only possible on the project page dropdown or on the commits page. This merge request both actions to the tree header dropdown. Now all repository web actions are available in this one location, plus the existing ones. It makes the operations a lot more intuitive.

## Existing Tree/Repository dropdown:

![Screen_Shot_2015-12-17_at_2.38.50_PM](/uploads/4d83a4b518093ea85f0859b385abcc7c/Screen_Shot_2015-12-17_at_2.38.50_PM.png)

## New Tree/Repository dropdown:

![Screen_Shot_2015-12-17_at_2.32.28_PM](/uploads/1fc18a511774630c5078a7d5c0fbb5b6/Screen_Shot_2015-12-17_at_2.32.28_PM.png)'

See merge request !2144

Remove duplicate entry in the changelog

/cc @DouweM 

See merge request !2149

Closes #4069

Use gitlab-shell 2.6.9

See merge request !2143