dashboard: show "-" if Node can't show cpu,ram usage, add bgcolor

circle/dashboard/templates/dashboard/node-list/column-monitor.html

@@ -5,7 +5,11 @@
  <div class="progress pull-right">
   <div class="progress-bar progress-bar-success" role="progressbar"
    aria-valuenow="{{ record.cpu_usage }}" aria-valuemin="0" aria-valuemax="1" style="width: 80%">
-   <span class="progress-bar-text">{{ record.cpu_usage|floatformat:1 }} % </span>
+   <span class="progress-bar-text">
+	   {% if record.cpu_usage != None %}
+	   {{ record.cpu_usage|floatformat:1 }}
+	   {% else %} - {% endif %} 
+   </span>
   </div>
  </div>
 <br>
@@ -13,7 +17,11 @@
  <div class="progress pull-right">
   <div class="progress-bar progress-bar-info" role="progressbar"
           aria-valuenow="{{ record.ram_usage}}" aria-valuemin="0" aria-valuemax="1" >
-   <span class="progress-bar-text"> {% widthratio record.byte_ram_usage 1048576 1 %} MB</span>
+	  <span class="progress-bar-text"> 
+		  {% if record.byte_ram_usage != None %}
+		  {% widthratio record.byte_ram_usage 1048576 1 %} MB
+	  	  {% else %} - {% endif %}
+	  </span>
   </div>
  </div>
 {% block "extra-js" %}
@@ -34,6 +42,7 @@ $('.progress-bar').each(function() {
     height: 12px;
     margin-bottom: 0px;
     margin-top: 5px;
+    background-image: linear-gradient(to bottom, #BBEBEB 0px, #F5F5F5 100%);
   }
   .progress-bar-text {
     position: absolute;