ssh-agent systemd user service failed to start, trying to set environment in Upstart way.

"systemctl --user status ssh-agent.service" give me the following info:
agent-launch[11327]: initctl: Name "com.ubuntu.Upstart" does not exist

As I'm running Systemd session instead of Upstart one, it shouldn't try to run initctl. So, I take a look at /usr/lib/openssh/agent-launcher. And this is what's in the file:

if type initctl >/dev/null 2>&1; then
    initctl set-env --global SSH_AUTH_SOCK=$S
fi

So, the script checks if Upstart is installed, but doesn't actually check if the current session is Upstart session or not. It has to check if $UPSTART_SESSION is defined or not.

$ lsb_release -a
LSB Version: core-9.20160110ubuntu5-amd64:core-9.20160110ubuntu5-noarch:printing-9.20160110ubuntu5-amd64:printing-9.20160110ubuntu5-noarch:security-9.20160110ubuntu5-amd64:security-9.20160110ubuntu5-noarch
Distributor ID: Ubuntu
Description: Ubuntu 17.04
Release: 17.04
Codename: zesty

$ LANG=C apt policy openssh-client
openssh-client:
  Installed: 1:7.4p1-10
  Candidate: 1:7.4p1-10
  Version table:
 *** 1:7.4p1-10 500
        500 http://th.archive.ubuntu.com/ubuntu zesty/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: openssh-client 1:7.4p1-10
ProcVersionSignature: Ubuntu 4.10.0-20.22-generic 4.10.8
Uname: Linux 4.10.0-20-generic x86_64
ApportVersion: 2.20.4-0ubuntu4
Architecture: amd64
CurrentDesktop: Unity:Unity7
Date: Mon May 8 17:51:09 2017
InstallationDate: Installed on 2013-04-23 (1475 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Alpha amd64 (20130402.1)
RelatedPackageVersions:
 ssh-askpass N/A
 libpam-ssh N/A
 keychain N/A
 ssh-askpass-gnome 1:7.4p1-10
SSHClientVersion: OpenSSH_7.4p1 Ubuntu-10, OpenSSL 1.0.2g 1 Mar 2016
SourcePackage: openssh
UpgradeStatus: Upgraded to zesty on 2017-04-29 (9 days ago)