When booting a porter board over NFS, the NFS connection to the server is lost when connman starts.

Details:
The following steps can be seen in the attached boot log:

• kernel start with: nfsroot=... and ip=dhcp
• the kernel starts the network interface and sets the IP address (192.168.111.1) as expected
• the kernel mounts the root fs ("VFS: Mounted root (nfs filesystem) ...")
• kernel boot ends and systemd takes over
• in the network target, connman starts as expected but brings the interface down before bringing it up and reconfiguring it
• during this operation, the nfs root connection is lost and reconnection seems impossible (or too long)