Log Message:
Update vtun package to 2.5.  Changes from 2.4:

ver 2.5:
	 New config option to keep tun device always open
	 iproute support
	 Fixes to support both Linux TUN/TAP drivers.

ver 2.5b1:
	 Encryption fixes: improved challenge generation, padding check.
	 Config parser fixes. Don't allow empty passwords.
	 New config option to specify syslog logging facility.
	 Support for new Linux TUN/TAP driver.
	 IO (read_n/write_n) cancellation.
	 Signal handling and other minor fixes.
	 Makefile improvement.
	 Documentation update.