upstart jobs broken and will not start after Debian merge

The upstart job of the new isc-dhcp-server package in saucy will not start, failing with this error:

Setting up isc-dhcp-server (4.2.4-7ubuntu1) ...
start: Job failed to start
invoke-rc.d: initscript isc-dhcp-server, action "start" failed.
dpkg: error processing isc-dhcp-server (--configure):
 subprocess installed post-installation script returned error exit status 1
E: Sub-process /usr/bin/dpkg returned an error code (1)

/var/log/upstart/isc-dhcp-server.log shows:

dhcpd self-test failed. Please fix the config file.
The error was:
Internet Systems Consortium DHCP Server 4.2.4
Copyright 2004-2012 Internet Systems Consortium.
All rights reserved.
Usage: dhcpd [-p <UDP port #>] [-f] [-d] [-q] [-t|-T]
             [-4|-6] [-cf config-file] [-lf lease-file]
             [-tf trace-output-file]
             [-play trace-input-file]
             [-pf pid-file] [--no-pid] [-s server]
             [if0 [...ifN]]

This is also reproducible on the commandline with:

sudo dhcpd -user dhcpd -group dhcpd -t -q -4 -cf /etc/dhcp/dhcpd.conf

I have no idea why this has suddenly started to fail after a package update, given that it's not a new upstream version; but clearly something has changed in the semantics of the dhcpd command, and the upstart job has not kept up.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: isc-dhcp-server 4.2.4-7ubuntu1
ProcVersionSignature: Ubuntu 3.10.0-1.8-generic 3.10.0-rc7
Uname: Linux 3.10.0-1-generic x86_64
ApportVersion: 2.10.2-0ubuntu4
Architecture: amd64
Date: Mon Jul 15 09:28:18 2013
InstallationDate: Installed on 2010-09-24 (1025 days ago)
InstallationMedia: Ubuntu 10.04.1 LTS "Lucid Lynx" - Release amd64 (20100816.1)
MarkForUpload: True
SourcePackage: isc-dhcp
UpgradeStatus: Upgraded to saucy on 2013-05-06 (69 days ago)
modified.conffile..etc.dhcp.dhcpd.conf: [modified]
mtime.conffile..etc.dhcp.dhcpd.conf: 2011-03-24T17:34:42