Merge branch 'hide-builds-tab' into 'master'

Hide Builds tab is GitLab CI is not enabled
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

See merge request !1627

app/helpers/projects_helper.rb

@@ -113,7 +113,7 @@ module ProjectsHelper
       nav_tabs << :merge_requests
     end
 
-    if can?(current_user, :read_build, project)
+    if project.gitlab_ci? && can?(current_user, :read_build, project)
       nav_tabs << :builds
     end