[one-users] minor fix for datastores tab

[Carlo Daffara]

Dear friends, on chrome (and for sure in Firefox nightly) the datastores tab does not properly line some of the pulldown menus; 
a very simple fix is to add an additional <br /> in datastores-tab.js at line 70, so that it becomes

  </select>*<br />*<br name="ds_mad" />\

little thing, I know :-)
cheers,
Carlo Daffara
CloudWeavers