Systemd service should not restart on failure

This should not be done by default but used by adminsys with a drop-in.d file,
for buggy daemons which crash without known fixes.

Docker-DCO-1.1-Signed-off-by: Sébastien Luttringer <seblu@seblu.net> (github: seblu)

contrib/init/systemd/docker.service

@@ -6,7 +6,6 @@ Requires=docker.socket
 
 [Service]
 ExecStart=/usr/bin/docker -d -H fd://
-Restart=on-failure
 LimitNOFILE=1048576
 LimitNPROC=1048576