coloring a datatable using date

I'm just testing, I want to leave the red font if the date is less than or equal to today

But nothing is happening I tried with '2017-02-21' '21 / 02/2017 'and it does not work

My css:

.vermelho {
    color: red;
}

My datatable:

<p:inputMask value="#{con.vencimento}" style="width:96%"
                            rowStyleClass="#{con.vencimento le '2017-02-21' ? 'vermelho' : null}"                           
                                mask="99/99/9999" label="vencimento">
                                <f:convertDateTime pattern="dd/MM/yyyy" />