Brackets added for incoming email comments using Exchange 2013

Summary

Incoming emails sent from Outlook over Exchange 2013 appear to have brackets added to the issue comment.

Steps to reproduce

1. Reply to an email from GitLab using Outlook

Expected behavior

New comment does not contain brackets.

Actual behavior

New comment contains two [ brackets.

Relevant logs and/or screenshots

Screenshots - GitLab Only

• https://drive.google.com/file/d/0B_4wYK1qcPT1X3BTTWJOM2JlZHc/view
• https://drive.google.com/file/d/0B_4wYK1qcPT1cVRHTGg0QVpXeDA/view

Raw Email - GitLab Only

• https://drive.google.com/a/gitlab.com/file/d/0B_4wYK1qcPT1TFBmYlFmN0Y5M0E/view?usp=sharing
• https://drive.google.com/a/gitlab.com/file/d/0B_4wYK1qcPT1MTJwLVV6c2RVZ2c/view?usp=sharing

Output of checks

• GitLab 8.16.3
• https://gitlab.zendesk.com/agent/tickets/58233
• https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7397