xhtml_style: remove hashes from icons.png URLs

this change was made with:

    find product/ERP5/bootstrap/erp5_xhtml_style/SkinTemplateItem/portal_skins/erp5_ckeditor/ckeditor/ -type f  | xargs sed -i 's/\\?t=445cf24ebd//g'
2 jobs for feat/nopyxml
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-TestRunner2

failed ERP5.UnitTest-TestRunner2