Reword backup min_time label

management/templates/system-backup.html

@@ -24,7 +24,7 @@
     </div>
   </div>
   <div class="form-group">
-    <label for="target" class="col-sm-2 control-label">Maximum time to keep old backups (in days)</label>
+    <label for="target" class="col-sm-2 control-label">How many days should backups be kept?</label>
     <div class="col-sm-8">
       <input type="number" class="form-control" rows="1" id="min-age"></input>
     </div>