Subscription stats: Make sure there can be no division by zero errors

sitescripts/logs/template/subscriptionOverview.html

 <!--
   - This file is part of the Adblock Plus web scripts,
   - Copyright (C) 2006-2012 Eyeo GmbH
   -
   - Adblock Plus is free software: you can redistribute it and/or modify
   - it under the terms of the GNU General Public License version 3 as
   - published by the Free Software Foundation.
   -
   - Adblock Plus is distributed in the hope that it will be useful,
   - but WITHOUT ANY WARRANTY; without even the implied warranty of
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       <tr>
         <td class="title" width="250">Last update:</td>
         <td>{{now|formattime}}</td>
       </tr>
     </table>
 
     <div class="block_title">Monthly history</div>
     <div class="block">
       <table align="center" style="margin-bottom: 20px;">
         <tr align="bottom">
-          {%- set maxHits, maxBandwidth = month|max(attribute='hits'), month|max(attribute='bandwidth') %}
-          {%- set totalHits = month|sum(attribute='hits') %}
-          {%- set totalBandwidth = month|sum(attribute='bandwidth') %}
+          {%- set maxHits = month|max(attribute='hits')|ensuremin(1) %}
+          {%- set maxBandwidth = month|max(attribute='bandwidth')|ensuremin(1) %}
+          {%- set totalHits = month|sum(attribute='hits')|ensuremin(1) %}
+          {%- set totalBandwidth = month|sum(attribute='bandwidth')|ensuremin(1) %}
           {%- for info in month %}
           <td align="center" style="vertical-align: bottom;">
             <div class="hitsChart vertical" title="Hits: {{info.hits}}" style="height: {{(info.hits / maxHits * 100)|round(method='ceil')|int}}px;"></div>
             {{- '' -}}
             <div class="bandwidthChart vertical" title="Bandwidth: {{info.bandwidth|bytes}}" style="height: {{(info.bandwidth / maxBandwidth * 100)|round(method='ceil')|int}}px;"></div>
           </td>
           {%- endfor %}
         </tr>
         <tr>
           {%- for info in month %}
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         <tr class="special">
           <td style="font-weight: bold">Total</td>
           <td align="right">{{totalHits}}</td>
           <td align="right">&nbsp;</td>
           <td align="right">{{totalBandwidth|bytes}}</td>
         </tr>
       </table>
     </div>
   </body>
 </html>