patternProperties keyword is not used in certain cases

[Stranger6667]

As reported by @duckontheweb in #183 the following schema compiles, but shouldn't:

{
    "type": "object",
    "properties": {
        "eo:cloud_cover": {
            "type": "number",
        },
    },
    "patternProperties": {
        "^(?!eo:)": {}
    },
    "additionalProperties": false
}

[Stranger6667]

So, compile_patterns(obj, context).ok()? transforms to None, but it should be Some(Err(...))