AMBARI-4018 config group description doesn't preserve multi-line. (ababiichuk)

ambari-web/app/styles/application.less

@@ -4977,7 +4977,12 @@ i.icon-asterisks {
     margin-top: 0px;
   }
   .manage-configuration-group-content {
-    margin-bottom: 30px;
+    margin-bottom: 0px;
+    .group-description {
+      height:40px;
+      overflow-y: auto;
+      white-space: pre;
+    }
   }
 }
 

ambari-web/app/templates/main/service/manage_configuration_groups_popup.hbs

@@ -74,7 +74,7 @@
         <div class="clearfix"></div>
         <div class="row-fluid">
           <div class="span2"><span class="prrl">{{t common.description}}</span></div>
-          <div class="span10">{{selectedConfigGroup.description}}</div>
+          <div class="span10 group-description">{{selectedConfigGroup.description}}</div>
         </div>
       </div>
       <div class="clearfix"></div>