Updated Docs README

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Merge pull request #5415 from jamtur01/readme2

Updated Docs README
Add Sockets (-H) list to `docker -D info`.

This will allow us to _know_ what the user's -H settings are, which may
be useful for debugging later.

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)