Fix DIGITS token so it does not accept leading 0

[yasny]

Trying to parse the following output of read-resource(attributes-only=true) lead to null being returned.

{
    "outcome" => "success",
    "result" => {
        "management-major-version" => 1,
        "management-micro-version" => 0,
        "management-minor-version" => 7,
        "name" => "Unnamed Domain",
        "namespaces" => [],
        "product-name" => "EAP",
        "product-version" => "6.4.0.GA",
        "release-codename" => "Janus",
        "release-version" => "7.5.0.Final-redhat-21",
        "schema-locations" => []
    }
}

Problem seems to be that the 0 for the management-micro-version was being tokenized as a DIGITS, as opposed to a ZERO.

I changed the DIGITS token to not accept a leading 0, and that allowed me to parse the output correctly.

[ph4r05]

Thanks for the PR! I am quite slammed at the moment and I would like to check it properly. Thanks for the provided example also! It may take a while to merge :/

Code is an adaptation of https://github.com/vsajip/json-ply for JBoss output grammar. The bug has to be present also there, hm.