[FIX] Attribute values in selectors must be attributes or strings
http://www.w3.org/TR/css3-selectors/#attribute-selectors
http://www.w3.org/TR/CSS21/syndata.html#value-def-identifier
> identifiers (including element names, classes, and IDs in selectors)
> can contain only the characters [a-zA-Z0-9] and ISO 10646 characters
> U+00A0 and higher, plus the hyphen (-) and the underscore (_); they
> cannot start with a digit, two hyphens, or a hyphen followed by a
> digit.
so "0" or "1" is not a valid identifier, must be a string and must
thus be quoted.
bzr revid: xmo@openerp.com-20131022142049-6fq70sielv95kmu0
Xavier Morel
ab20dbc885