style(dashboard): change the icon in the main widget (#102)

app/components/dashboard/dashboard.html

@@ -8,7 +8,7 @@
 <div class="row">
   <div class="col-lg-12 col-md-12 col-xs-12" ng-if="!swarm">
     <rd-widget>
-      <rd-widget-header icon="fa-cogs" title="Node info"></rd-widget-header>
+      <rd-widget-header icon="fa-tachometer" title="Node info"></rd-widget-header>
       <rd-widget-body classes="no-padding">
         <table class="table">
           <tbody>
@@ -35,7 +35,7 @@
   </div>
   <div class="col-lg-12 col-md-12 col-xs-12" ng-if="swarm">
     <rd-widget>
-      <rd-widget-header icon="fa-cogs" title="Cluster info"></rd-widget-header>
+      <rd-widget-header icon="fa-tachometer" title="Cluster info"></rd-widget-header>
       <rd-widget-body classes="no-padding">
         <table class="table">
           <tbody>