Fix a problem where a nul byte was wrongly introduced into UUIDs, due to _dbus_string_copy_to_buffer weird behavior.

2007-10-31  Havoc Pennington  <hp@redhat.com>

	* bus/selinux.c (log_audit_callback): rewrite to use
	_dbus_string_copy_to_buffer_with_nul()

	* dbus/dbus-string.c (_dbus_string_copy_to_buffer): change to NOT
	nul-terminate the buffer; fail an assertion if there is not enough
	space in the target buffer. This fixes two bugs where
	copy_to_buffer was used to copy the binary bytes in a UUID, where
	nul termination did not make sense. Bug reported by David Castelow.
	(_dbus_string_copy_to_buffer_with_nul): new function that always
	nul-terminates the buffer, and fails an assertion if there is not
	enough space in the buffer.