Fix issues bulk update from issues index page

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

app/views/projects/issues/_issues.html.haml

-%ul.content-list.issues-list
+%ul.content-list.issues-list.issuable-list
   = render @issues
   - if @issues.blank?
     %li

app/views/projects/issues/index.html.haml

@@ -31,7 +31,7 @@
             New Issue
     = render 'shared/issuable/filter', type: :issues
-    .issues-holder.issuable-list
+    .issues-holder
       = render 'issues'
       - if new_issue_email
         = render 'issue_by_email', email: new_issue_email