Skip description if not exist

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/views/search/results/_issue.html.haml

@@ -3,6 +3,7 @@
     = link_to [issue.project, issue] do
       %span.term.str-truncated= issue.title
     .pull-right ##{issue.iid}
+  - if issue.description.present?
     .description.term
       = preserve do
         = search_md_sanitize(markdown(issue.description))