engine/security: add more description about ssh://

Previously, the `ssh://` helper was only mentioned in `engine/security/index.md`.

The `ssh://` helper is now documented in "Protect the Docker daemon socket"
(`engine/security/protect-access.md`, nee `engine/security/https.md`).

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

engine/security/https/README.md

@@ -2,7 +2,7 @@
 published: false
 ---
 
-This is an initial attempt to make it easier to test the examples in the https.md
+This is an initial attempt to make it easier to test the TLS (HTTPS) examples in the protect-access.md
 doc.
 
 At this point, it is a manual thing, and I've been running it in boot2docker.

engine/security/https/parsedocs.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 
 echo "#!/bin/sh"
-cat ../https.md | awk '{if (sub(/\\$/,"")) printf "%s", $0; else print $0}' \
+cat ../protect-access.md | awk '{if (sub(/\\$/,"")) printf "%s", $0; else print $0}' \
         | grep '   $ ' \
         | sed 's/    $ //g' \
         | sed 's/2375/7777/g' \