#4704 Add yaboot boot password support

[Bill Wajda]

Change adds a new parameter to the nodeset command "--password <pw>".
If set it adds two lines in the yaboot.conf file for the nodes:
password=<pw>
restricted</pw></pw>

The <pw> can be plaintext or anything the linux password tools will take as an encrypted password, details are in the crypt(3) man page.</pw>

[Bill Wajda]

checked in changes to yaboot.pm and nodeset.8.pod in commit:
b90e1933262fa56a1b01397eec43ef1f1e3593e8