Fix optional parameter getStats($type)

[ackintosh]

type is optional, but ReflectionParameter::isOptional() returns false.

example

        $method = new \ReflectionMethod(new \Memcached(), 'getStats');
        foreach ($method->getParameters() as $p) {
            var_dump($p->name, $p->isOptional());
        }

before

string(4) "args"
bool(false)

after

string(4) "type"
bool(true)

[sodabrew]

Thanks for the contribution!

[stolenegg]

Many thanks for this fix - it was causing an issue in some of our unit tests (mocked instances were incorrectly requiring the optional parameter) 👍