Verification Email will not send due to errors caused by Docker filesystem

It appears the – prefix is not used in newer docker versions so I ran the commands without it.

The command docker info returns:

Containers: 1
Images: 11
Storage Driver: overlay
 Backing Filesystem: extfs
Execution Driver: native-0.2
Logging Driver: json-file
Kernel Version: 4.1.5-x86_64-linode61
Operating System: Gentoo/Linux
CPUs: 2
Total Memory: 1.952 GiB
Name: linodevps
ID: 2C7H:MOAS:GM2N:JMG7:GYY5:CNNF:R33M:QNKK:3U6K:2N27:OOAU:PZRG
WARNING: No swap limit support

The command docker version returns:

Client:
 Version:      1.8.1
 API version:  1.20
 Go version:   go1.4.2
 Git commit:   d12ea79
 Built:
 OS/Arch:      linux/amd64

Server:
 Version:      1.8.1
 API version:  1.20
 Go version:   go1.4.2
 Git commit:   d12ea79
 Built:
 OS/Arch:      linux/amd64

Also, in case it matters, when merging the docker package the following notice appeared:

 * Checking for suitable kernel configuration options...
 *   CONFIG_MEMCG_KMEM: is optional
 *   CONFIG_MEMCG_SWAP: is required if you wish to limit swap usage of containers
 *   CONFIG_MEMCG_SWAP_ENABLED:  is not set when it should be.
 *   CONFIG_CGROUP_HUGETLB:      is not set when it should be.
 *   CONFIG_RT_GROUP_SCHED:      is not set when it should be.