Remove CSS property preventing hard tabs from rendering in Chromium 45

This is to workaround a bug in Chromium 45 (https://code.google.com/p/chromium/issues/detail?id=446434),
which is the default browser in Ubuntu 14.04 and older.

Closes #3220

CHANGELOG

@@ -1,6 +1,7 @@
 Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.2.0 (unreleased)
+  - Remove CSS property preventing hard tabs from rendering in Chromium 45 (Stan Hu)
   - Added a GitLab specific profiling tool called "Sherlock" (see GitLab CE merge request #1749)
   - Upgrade gitlab_git to 7.2.20 and rugged to 0.23.3 (Stan Hu)
   - Fix bug where manually merged branches in a MR would end up with an empty diff (Stan Hu)

app/assets/stylesheets/framework/typography.scss

@@ -173,7 +173,6 @@
  *
  */
 body {
-  text-rendering:optimizeLegibility;
   -webkit-text-shadow: rgba(255,255,255,0.01) 0 0 1px;
 }