Merge branch 'make_milestone_labels_tab_similar_to_labels_page' into 'master'

Make milestone labels in labels tab similar to that of the labels page

I realized that some of the changes for the labels page was not reflecting in the labels list in milestone page.

## Desktop
![Screen_Shot_2016-04-11_at_4.25.36_PM](/uploads/e21f3c5a9187fe32472e796171781b5d/Screen_Shot_2016-04-11_at_4.25.36_PM.png)

## Mobile
![Screen_Shot_2016-04-11_at_4.26.47_PM](/uploads/5c9f75ca0938fc30ab47c5520215f692/Screen_Shot_2016-04-11_at_4.26.47_PM.png)


See merge request !3658

app/assets/stylesheets/pages/labels.scss

@@ -79,19 +79,30 @@
   color: $white-light;
 }
 
+@mixin labels-mobile {
+  @media (max-width: $screen-xs-min) {
+    display: block;
+    width: 100%;
+    margin-left: 0;
+    padding: 10px 0;
+  }
+}
+
+
 .manage-labels-list {
 
-  .prepend-left-10 {
+  .prepend-left-10, .prepend-description-left {
     display: inline-block;
     width: 40%;
     vertical-align: middle;
 
-    @media (max-width: $screen-xs-min) {
-      display: block;
-      width: 100%;
-      margin-left: 0;
-      padding: 10px 0;
-    }
+    @include labels-mobile;
+  }
+
+  .prepend-description-left {
+    width: 57%;
+
+    @include labels-mobile;
   }
 
   .pull-info-right {

app/views/shared/milestones/_labels_tab.html.haml

@@ -4,15 +4,16 @@
 
     %li
       %span.label-row
-        = link_to milestones_label_path(options) do
-          - render_colored_label(label, tooltip: false)
-        %span.prepend-left-10
+        %span.label-name
+          = link_to milestones_label_path(options) do
+            - render_colored_label(label, tooltip: false)
+        %span.prepend-description-left
           = markdown(label.description, pipeline: :single_line)
 
-      .pull-right
-        %strong.issues-count
+      .pull-info-right
+        %span.append-right-20
           = link_to milestones_label_path(options.merge(state: 'opened')) do
             - pluralize milestone_issues_by_label_count(@milestone, label, state: :opened), 'open issue'
-        %strong.issues-count
+        %span.append-right-20
           = link_to milestones_label_path(options.merge(state: 'closed')) do
             - pluralize milestone_issues_by_label_count(@milestone, label, state: :closed), 'closed issue'