moby: Plugin not found message in daemon log

Description

After installing a plugin (netapp/ndvp), some repetitive error messages appear in the daemon log.

Jan 12 09:44:00 host1 dockerd[14753]: time="2018-01-12T09:44:00.014410367+01:00" level=error msg="plugin not found"
Jan 12 09:43:55 host1 dockerd[14753]: time="2018-01-12T09:43:55.798532970+01:00" level=error msg="plugin not found"
Jan 12 09:43:18 host1 dockerd[14753]: time="2018-01-12T09:43:18.554964465+01:00" level=error msg="plugin not found"
Jan 12 09:43:10 host1 dockerd[14753]: time="2018-01-12T09:43:10.415306479+01:00" level=error msg="plugin not found"
Jan 12 09:43:01 host1 dockerd[14753]: time="2018-01-12T09:43:01.650009043+01:00" level=error msg="plugin not found"
Jan 12 09:42:29 host1 dockerd[14753]: time="2018-01-12T09:42:29.129704504+01:00" level=error msg="plugin not found"
Jan 12 09:42:26 host1 dockerd[14753]: time="2018-01-12T09:42:26.203150845+01:00" level=error msg="plugin not found"
Jan 12 09:42:08 host1 dockerd[14753]: time="2018-01-12T09:42:08.936892945+01:00" level=error msg="plugin not found"
Jan 12 09:41:57 host1 dockerd[14753]: time="2018-01-12T09:41:57.008843300+01:00" level=error msg="plugin not found"

Steps to reproduce the issue:

1. Install netapp/ndvp plugin ( http://netappdvp.readthedocs.io/en/latest/install/host_config.html )
2. journalctl -u docker.service

Describe the results you received:

Jan 12 09:44:00 host1 dockerd[14753]: time="2018-01-12T09:44:00.014410367+01:00" level=error msg="plugin not found"
Jan 12 09:43:55 host1 dockerd[14753]: time="2018-01-12T09:43:55.798532970+01:00" level=error msg="plugin not found"
Jan 12 09:43:18 host1 dockerd[14753]: time="2018-01-12T09:43:18.554964465+01:00" level=error msg="plugin not found"
Jan 12 09:43:10 host1 dockerd[14753]: time="2018-01-12T09:43:10.415306479+01:00" level=error msg="plugin not found"
Jan 12 09:43:01 host1 dockerd[14753]: time="2018-01-12T09:43:01.650009043+01:00" level=error msg="plugin not found"
Jan 12 09:42:29 host1 dockerd[14753]: time="2018-01-12T09:42:29.129704504+01:00" level=error msg="plugin not found"
Jan 12 09:42:26 host1 dockerd[14753]: time="2018-01-12T09:42:26.203150845+01:00" level=error msg="plugin not found"
Jan 12 09:42:08 host1 dockerd[14753]: time="2018-01-12T09:42:08.936892945+01:00" level=error msg="plugin not found"
Jan 12 09:41:57 host1 dockerd[14753]: time="2018-01-12T09:41:57.008843300+01:00" level=error msg="plugin not found"

Describe the results you expected: No error in the log

Additional information you deem important (e.g. issue happens only occasionally):

Output of docker version:

Client:
 Version:       17.12.0-ce
 API version:   1.35
 Go version:    go1.9.2
 Git commit:    c97c6d6
 Built: Wed Dec 27 20:11:19 2017
 OS/Arch:       linux/amd64

Server:
 Engine:
  Version:      17.12.0-ce
  API version:  1.35 (minimum version 1.12)
  Go version:   go1.9.2
  Git commit:   c97c6d6
  Built:        Wed Dec 27 20:09:53 2017
  OS/Arch:      linux/amd64
  Experimental: false

Output of docker info:

Containers: 13
 Running: 13
 Paused: 0
 Stopped: 0
Images: 15
Server Version: 17.12.0-ce
Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true
 Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 89623f28b87a6004d4b785663257362d1658a729
runc version: b2567b37d7b75eb4cf325b77297b140ea686ce8f
init version: 949e6fa
Security Options:
 apparmor
 seccomp
  Profile: default
 userns
Kernel Version: 4.4.0-109-generic
Operating System: Ubuntu 16.04.3 LTS
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 15.67GiB
Name: host1
ID: MIFR:GSOU:P4FI:ZIFY:FTD6:BZ4M:U6KV:NDX2:W3VV:J6AM:MYIQ:POSN
Docker Root Dir: /var/lib/docker/100000.100000
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Cluster Store: etcd://localhost:2379
Cluster Advertise: 192.168.1.29:2376
Insecure Registries:
 127.0.0.0/8
Registry Mirrors:
 https://myregistry.com/
Live Restore Enabled: true

WARNING: No swap limit support

Additional environment details (AWS, VirtualBox, physical, etc.): Ubuntu VM:

Linux host1 4.4.0-109-generic #132-Ubuntu SMP Tue Jan 9 19:52:39 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux