Fix missing custom apache2 unit file directory

For the upgrade tests:

Jun 30 15:14:48    - [citest00027218] Error: Could not set 'file' on ensure: No such file or directory @ dir_s_rmdir - /etc/systemd/system/apache2.service.d/autorestart.conf20170630-30402-1mgmk6k.lock at 21:/srv/leap/puppet/modules/systemd/manifests/unit_file.pp
Jun 30 15:14:48    - [citest00027218] Error: Could not set 'file' on ensure: No such file or directory @ dir_s_rmdir - /etc/systemd/system/apache2.service.d/autorestart.conf20170630-30402-1mgmk6k.lock at 21:/srv/leap/puppet/modules/systemd/manifests/unit_file.pp
Jun 30 15:14:48    - [citest00027218] Wrapped exception:
Jun 30 15:14:48    - [citest00027218] No such file or directory @ dir_s_rmdir - /etc/systemd/system/apache2.service.d/autorestart.conf20170630-30402-1mgmk6k.lock
Jun 30 15:14:48    - [citest00027218] Error: /Stage[main]/Site_apache::Common::Autorestart/Systemd::Unit_file[apache2.service.d/autorestart.conf]/File[/etc/systemd/system/apache2.service.d/autorestart.conf]/ensure: change from absent to file failed: Could not set 'file' on ensure: No such file or directory @ dir_s_rmdir - /etc/systemd/system/apache2.service.d/autorestart.conf20170630-30402-1mgmk6k.lock at 21:/srv/leap/puppet/modules/systemd/manifests/unit_file.pp

The /etc/systemd/system/apache2.service.d is missing:

root@runner--project-0-concurrent-0:/# ls -al /etc/systemd/system
total 32
drwxr-xr-x 1 root root 4096 May 30 14:19 .
drwxr-xr-x 1 root root 4096 May  8 21:56 ..
drwxr-xr-x 2 root root 4096 May  8 21:56 getty.target.wants
drwxr-xr-x 2 root root 4096 May  8 21:56 halt.target.wants
drwxr-xr-x 1 root root 4096 May 30 14:19 multi-user.target.wants
drwxr-xr-x 2 root root 4096 May  8 21:56 poweroff.target.wants
drwxr-xr-x 2 root root 4096 May  8 21:56 reboot.target.wants
drwxr-xr-x 2 root root 4096 May 30 14:19 sockets.target.wants