Revert "systemd: add multi-user.target to After list"

This reverts commit a65c65d801f7c05f38efb0deb7917d598078afc1,
which caused the docker service to not be starting, or delayed
starting the service in certain conditions.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

contrib/init/systemd/docker.service

@@ -1,7 +1,7 @@
 [Unit]
 Description=Docker Application Container Engine
 Documentation=https://docs.docker.com
-After=network-online.target firewalld.service containerd.service multi-user.target
+After=network-online.target firewalld.service containerd.service
 Wants=network-online.target
 Requires=docker.socket containerd.service