ssh-agent env variables not set when not using Bourne shell

When I start an X session (default gnome/unity setup) I find that ssh-agent is started but the appropriate environment variables (SSH_AGENT_PID, SSH_AUTH_SOCK) are not set. .xsession-errors contains:

init: ssh-agent pre-start process (1797) terminated with status 127

The problem appears to be in /usr/share/upstart/sessions/ssh-agent.conf. It evals ssh-agent expecting the output to be valid Bourne shell syntax however ssh-agent checks (IIUC) the user's shell and output C shell style code if the user is using a C based shell. I use tcsh and so get output like 'setenv SSH_AGENT_PID ...' from ssh-agent. This of course fails to set any environment variables in the Bourne shell script that the upstart job effectively is.

Luckily ssh-agent has a flag to ask for Bourne shell syntax.

--- ssh-agent.conf.orig 2013-10-07 11:30:08.546222472 +0200
+++ ssh-agent.conf 2013-10-07 11:30:30.858221774 +0200
@@ -7,7 +7,7 @@
     [ -e /etc/X11/Xsession.options ] || { stop; exit 0; }
     grep -q "^use-ssh-agent$" /etc/X11/Xsession.options || { stop; exit 0; }

- eval "$(ssh-agent)" >/dev/null
+ eval "$(ssh-agent -s)" >/dev/null
     initctl set-env --global SSH_AUTH_SOCK=$SSH_AUTH_SOCK
     initctl set-env --global SSH_AGENT_PID=$SSH_AGENT_PID
 end script

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: openssh-client 1:6.2p2-6 [modified: usr/share/upstart/sessions/ssh-agent.conf]
ProcVersionSignature: Ubuntu 3.11.0-11.17-generic 3.11.3
Uname: Linux 3.11.0-11-generic x86_64
ApportVersion: 2.12.5-0ubuntu1
Architecture: amd64
Date: Mon Oct 7 12:50:45 2013
InstallationDate: Installed on 2013-06-28 (101 days ago)
InstallationMedia: Ubuntu 12.04.2 LTS "Precise Pangolin" - Release amd64 (20130213)
MarkForUpload: True
RelatedPackageVersions:
 ssh-askpass N/A
 libpam-ssh N/A
 keychain N/A
 ssh-askpass-gnome 1:6.2p2-6
SSHClientVersion: OpenSSH_6.2p2 Ubuntu-6, OpenSSL 1.0.1e 11 Feb 2013
SourcePackage: openssh
UpgradeStatus: Upgraded to saucy on 2013-09-23 (14 days ago)