ptpd2: new package

Add the ptpd2 package, handles the IEEE 1588-2008 spec which is not
backward compatible to IEEE 1588-2002.

[Peter: mark init script as executable]
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>