make error message when running commands while daemon is down more user-friendly.
```
docker@54.175.201.239 ~: sudo service docker stop
docker stop/waiting
docker@54.175.201.239 ~: docker images
Get http:///var/run/docker.sock/v1.19/images/json: dial unix /var/run/docker.sock: no such file or directory. Are you trying to connect to a TLS-enabled daemon without TLS?
```
Signed-off-by: Damien Nozay <damien.nozay@gmail.com>
Upstream-commit: e9ac7d24a7de5e009f74887cf21f15b6bb4e4605
Component: engine
d924a293ae