Add ssl-offloading load balancer configuration document.

[zongzw]

@jputrino @zhaoqin-github

What's this change do?

Add ssl offloading document.

[selhorn]

@jputrino This looks good to me--I believe your approval is needed to merge.

[zongzw]

Oops, Just notice that there's a travis ci failure because of - The inputs are validated when you enter them. The *Create* button is available ^^^^^^^^^^^^^ "are validated" may be passive voice on line 51 at column 13

@selhorn I wonder how do you handle such case. Seems passive voice here is better than 'active'.

[selhorn]

You're right that sometimes passive sounds more natural. But to make it active, just start with who does the acting. "Openstack validates your entries." Or you can delete this sentence. People will see that their entries are being validated, so there's no need for the documentation to repeat this information.

[zongzw]

Thanks @selhorn your sugguestion of delete it is ok to me. updated it. However, I have to ask one more question, consequently, since passive is more natural 'sometimes', why do we have such restriction in scripts/test-docs.sh:11:write-goodfind ./docs -not ( -path ./docs/drafts -prune ) -name '*.rst'--passive --so --no-illusion --thereIs --cliches? @selhorn @jputrino

Anyhow, it doesn't block 'Merge pull request', it may have been merged when you see my comment. .

[zongzw]

@zhaoqin-github right, sni and p12 description can be added optionally in future. for your comment of version restriction, I updated it as a table. please review.