DEVELOPERS: drop Trent Piepho

We change Trent's e-mail address in commit
1c20802d, but it turns out the new one
also doesn't work:

<trent.piepho@synapse.com>: host
    synapse-com.mail.protection.outlook.com[104.47.57.138] said: 550 5.4.1
    Recipient address rejected: Access denied. AS(201806281)
    [DM6NAM11FT063.eop-nam11.prod.protection.outlook.com] (in reply to RCPT TO
    command)

So let's drop Trent entirely, which orphans the libp11 package.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>