Only show register tab if signup enabled.

CHANGELOG.md

@@ -20,6 +20,7 @@ Please view this file on the master branch, on stable branches it's out of date.
   - Fix 404 for group pages when GitLab setup uses relative url
   - Simpler arguments passed to named_route on toggle_award_url helper method 
   - Better handle when no users were selected for adding to group or project. (Linus Thiel)
+  - Only show register tab if signup enabled.
 
 ## 8.13.0 (2016-10-22)
   - Removes extra line for empty issue description. (!7045)

app/views/devise/shared/_tabs_normal.html.haml

 %ul.nav-links.new-session-tabs.nav-tabs{ role: 'tablist'}
   %li.active{ role: 'presentation' }
     %a{ href: '#login-pane', data: { toggle: 'tab' }, role: 'tab'} Sign in
+  - if signin_enabled? && signup_enabled?
     %li{ role: 'presentation'}
       %a{ href: '#register-pane', data: { toggle: 'tab' }, role: 'tab'} Register