moby: Frequent log message: failed to retrieve docker-init version

After upgrading a host from Docker 1.12.3 to 1.13.0-rc1, I’m seeing this message in the logs every 20 seconds:

time="2016-11-16T19:51:31.192624068Z" level=warning msg="failed to retrieve docker-init version: unknown output format"

# docker version
Client:
 Version:      1.13.0-rc1
 API version:  1.25
 Go version:   go1.7.3
 Git commit:   75fd88b
 Built:        Fri Nov 11 19:41:05 2016
 OS/Arch:      linux/amd64

Server:
 Version:             1.13.0-rc1
 API version:         1.25
 Minimum API version: 1.12
 Go version:          go1.7.3
 Git commit:          75fd88b
 Built:               Fri Nov 11 19:41:05 2016
 OS/Arch:             linux/amd64
 Experimental:        false

# docker info
Containers: 4
 Running: 2
 Paused: 0
 Stopped: 2
Images: 1
Server Version: 1.13.0-rc1
Storage Driver: aufs
 Root Dir: /var/lib/docker/aufs
 Backing Filesystem: extfs
 Dirs: 15
 Dirperm1 Supported: false
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay
Swarm: active
 NodeID: dw0lwvpnl1qyablsx9qymm0xc
 Is Manager: true
 ClusterID: 1y6spf1vqrxndmu1x1icuji2c
 Managers: 2
 Nodes: 2
 Orchestration:
  Task History Retention Limit: 5
 Raft:
  Snapshot Interval: 10000
  Number of Old Snapshots to Retain: 0
  Heartbeat Tick: 1
  Election Tick: 3
 Dispatcher:
  Heartbeat Period: 5 seconds
 CA Configuration:
  Expiry Duration: 3 months
 Node Address: 172.31.11.220
 Manager Addresses:
  52.23.174.225:2377
  54.209.84.184:2377
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 8517738ba4b82aff5662c97ca4627e7e4d03b531
runc version: ac031b5bf1cc92239461125f4c1ffb760522bbf2
init version: N/A (expected: v0.13.0)
Security Options:
 apparmor
Kernel Version: 3.13.0-92-generic
Operating System: Ubuntu 14.04.4 LTS
OSType: linux
Architecture: x86_64
CPUs: 1
Total Memory: 992.5 MiB
Name: ip-172-31-11-220
ID: 2GKH:OS2J:AS52:MPMM:JB2N:IW7L:WSD7:K5FY:I3ED:6LB2:TPWQ:J3RM
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
WARNING: No swap limit support
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false