[WIP] Update `motd` in `Trusty`

Noticed that the `/etc/motd` is not updated in `Trusty`.
This commit is intended to update `etc/motd` in `Trusty`.
[base] Deploy the script for updating `/etc/motd` in `Trusty`.
[base] Add test for updating `/etc/motd` in `Trusty`.
Merge pull request #167 from kazu634/motd-update-trusty

Update `motd` in `Trusty`