Previously, when `pw_protocol_pulse_new()` returned NULL,
the code would jump to the `error` label, which would
call `impl_free()`. At this point, however, `impl->module_listener`
is not initialized, which would lead to a SIGSEGV when
`spa_hook_remove()` is called from `impl_free()`.
There is no need to copy the properties, just pass ownership.
Make sure to always have properties for the server. Ensure we
clean up properties on error.