bitbake: toaster: Fix toastertable header

Fixes regression introduced by 'tables updates for HTML5 compliance'

(Bitbake rev: 406a7f81420f7baa5cbfc034b573a4d692b98874)

Signed-off-by: Michael Wood <michael.g.wood@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/toaster/toastergui/templates/toastertable.html

@@ -93,6 +93,7 @@
   <!-- The actual table -->
   <table class="table table-bordered table-hover tablesorter" id="{{table_name}}">
     <thead id="tableheader">
+      <tr><th></th></tr>
     </thead>
     <tbody></tbody>
   </table>