Revert "Add multi-user.target to After="

This reverts commit 0ca7456e5284d4aa9f3e37e69c7c93eff4420d3d,
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 docker.socket firewalld.service multi-user.target
+After=network-online.target docker.socket firewalld.service
 Wants=network-online.target
 Requires=docker.socket