Remove dependency on missing UnixSystem class

[Martmists-GH]

Exception in thread "main" java.lang.NoClassDefFoundError: com/sun/security/auth/module/UnixSystem
	at org.freedesktop.dbus.connections.SASL.getUserId(SASL.java:757)
	at org.freedesktop.dbus.connections.SASL.auth(SASL.java:459)
	at org.freedesktop.dbus.connections.transports.AbstractTransport.authenticate(AbstractTransport.java:254)
	at org.freedesktop.dbus.connections.transports.AbstractTransport.internalConnect(AbstractTransport.java:230)
	at org.freedesktop.dbus.connections.transports.AbstractTransport.connect(AbstractTransport.java:177)
	at org.freedesktop.dbus.connections.transports.TransportBuilder.build(TransportBuilder.java:213)
	at org.freedesktop.dbus.connections.base.AbstractConnectionBase.<init>(AbstractConnectionBase.java:114)
	at org.freedesktop.dbus.connections.base.ConnectionMethodInvocation.<init>(ConnectionMethodInvocation.java:33)
	at org.freedesktop.dbus.connections.base.ConnectionMessageHandler.<init>(ConnectionMessageHandler.java:42)
	at org.freedesktop.dbus.connections.AbstractConnection.<init>(AbstractConnection.java:41)
	at org.freedesktop.dbus.connections.impl.DBusConnection.<init>(DBusConnection.java:72)
	at org.freedesktop.dbus.connections.impl.DBusConnectionBuilder.build(DBusConnectionBuilder.java:176)

[hypfvieh]

Some more context would be helpful.

The call to UnixSystem is completely valid on any *nix OS.
Do you use a custom tailored JRE and forgot to include the jdk.security.auth module?