[hacknews] uuxqt lock-time fix

henry (11/15/82)

Increased the length of time it takes before uuxqt decides that an
old uuxqt lock is spurious;  4 hours is not always enough for us.
Having two running at the same time produces inordinately slow response
elsewhere, very slow execution of the uuxqt's themselves, and frequent
locking clashes in onward transmission of news and mail.

I intend to do some filesystem shuffling soon, which should greatly
improve the performance of the news system and the network software.