Fix encoding issue in check_git_config

Fix encoding issue in check_git_config

Fix for
"Unicode equal comparison failed to convert both arguments to Unicode"
when the git username contains non-ascii characters. Fixed by
utf-8 decoding data imported from git.

BUG=521519
Committed: https://crrev.com/7813ff35ac515acf6bf5e282081d5a9a54b30fc7
Cr-Commit-Position: refs/heads/master@{#343836}

[drott, 2015-08-17 08:58:42]

drott@chromium.org changed reviewers:
+ groby@chromium.org, vadimsh@chromium.org

[Vadim Sh., 2015-08-17 17:40:54]

lgtm, thanks

[drott, 2015-08-18 06:14:35]

The CQ bit was checked by drott@chromium.org

[commit-bot: I haz the power, 2015-08-18 06:14:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1301453003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1301453003/1

[commit-bot: I haz the power, 2015-08-18 06:27:06]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-18 06:27:43]

Patchset 1 (id:??) landed as
https://crrev.com/7813ff35ac515acf6bf5e282081d5a9a54b30fc7
Cr-Commit-Position: refs/heads/master@{#343836}