The "service" resource is a purely internal structure used by
SoapServer, which userland code cannot interact with. Instead of
storing it as a resource in an object propperty, use a custom
object structure instead.
This was previously implicitly public due to the use of dynamic
properties. Make this internal state private.
If someone complains, we can consider relaxing this to protected
or public on a case-by-case basis.
Currently an empty string is used to unset the location. Once
again, it makes more sense to use a null value for this purpose
(though the special behavior of empty strings is retained).
The code comment above the function also explicitly indicates
that null should be accepted, and the function does return null
rather than an empty string for the old location value (if it
is missing).
$typeName, $typeNamespace, $nodeName and $nodeNamespace all
special-case the empty string and don't set the property entirely
in that case. It makes more sense to use null to indicate absence
here (though of course the empty string behavior is retained).
