Fix for a "500: Encoding error" in the blame view

What does this MR do?

- The change enforces UTF-8 encoding on the source line data obtained from the Git.

Are there points in the code the reviewer needs to double check?

- The fix might not be enough to fix all encoding error issues in the blame view. There might be similar encoding issues if there are non-UTF-8 encoded names, for example

Why was this MR needed?

- This change fixes the "500: encoding error" that I get when I try to view the Gitlab source CHANGELOG file.

What are the relevant issue numbers / Feature requests?

- Gitlab issue #894: https://gitlab.com/gitlab-org/gitlab-ce/issues/894

See merge request !298

Mwessel/gitlab ce configure protection

See merge request !1467

Remove hidden settings text on project settings

No need to have the hidden settings text anymore as the danger area is now unified.

See merge request !320

Fix raw image paste from clipboard

Fix capitalization of URL.

A targeted fix in the documentation.

See merge request !323

Webhook rescue Errno::ECONNRESET

Fixes #1821

See merge request !1466

Collapseable sidebar

See merge request !1465

Merge branch 'collapseable-nav' of https://github.com/jasonblanchard/gitlabhq into jasonblanchard-collapseable-nav

Push it

Spelling improvement

See merge request !1464

Merge branch 'issue-merge-req-context-links' of https://github.com/jasonblanchard/gitlabhq into jasonblanchard-issue-merge-req-context-links

Conflicts:
	CHANGELOG

Web editor documentation

Related to #1930

See merge request !1458

Access groups using path

Made diff colors a little less In Your Face

Tune commit page: async load of branch info

See merge request !1462

Conflicts:
	config/routes.rb

viewports for issues and merge requests

Update gitlab-shell to 2.4.2 for 7.7 install/update guide

closes #8718, closes #8721

Signed-off-by: Jeroen van Baarsen <jeroenvanbaarsen@gmail.com>

Rubycop improvements

See merge request !1463