* bus/connection.c: (connection_error_handler),
	(bus_connection_setup):
	* bus/main.c: (main):
	Make sure that the DBusConnectionData struct is NULLed
	out to prevent a segfault.

	* dbus/dbus-errors.c: (dbus_result_to_string):
	* dbus/dbus-errors.h:
	* dbus/dbus-message.c: (dbus_message_get_fields),
	(dbus_message_get_fields_valist), (_dbus_message_test):
	* dbus/dbus-message.h:
	Make dbus_message_get_fields return a result code so we can
	track invalid fields as well as oom.