[Web UI] Wrong value in filesystem plugin (issue #662)

glances/outputs/static/html/plugins/fs.html

@@ -6,7 +6,7 @@
 <div class="table-row" ng-repeat="fs in statsFs.fileSystems | orderBy:  'mnt_point'">
     <div class="table-cell text-left">{{ fs.mountPoint }} ({{ fs.name }})</div>
     <div class="table-cell" ng-class="statsFs.getDecoration(fs.mountPoint, 'used')">
-        {{ fs.size - fs.free | bytes }}
+        {{ fs.used | bytes }}
     </div>
     <div class="table-cell">{{ fs.size | bytes }}</div>
 </div>

glances/outputs/static/js/services/plugins/glances_fs.js

@@ -16,6 +16,7 @@ glancesApp.service('GlancesPluginFs', function() {
                 'mountPoint': fsData['mnt_point'],
                 'percent': fsData['percent'],
                 'size': fsData['size'],
+                'used': fsData['used'],
                 'free': fsData['free']
             };