Fix labels showing if issue closed on search results page

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

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

@@ -6,4 +6,4 @@
       = truncate issue.title, length: 50
   %span.light (#{issue.project.name_with_namespace})
   - if issue.closed?
-    %span.label Closed
+    %span.label.label-danger Closed

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

@@ -8,5 +8,7 @@
     %span.light (#{merge_request.source_project.name_with_namespace}:#{merge_request.source_branch} → #{merge_request.target_project.name_with_namespace}:#{merge_request.target_branch})
   - else
     %span.light (#{merge_request.source_branch} → #{merge_request.target_branch})
-  - if merge_request.closed?
-    %span.label Closed
+  - if merge_request.merged?
+    %span.label.label-primary Merged
+  - elsif merge_request.closed?
+    %span.label.label-danger Closed