Updating LxcConf to match Docker command line

I've changed LxcConf on a previous API document. Not sure why it keeps getting changed back. I'm seeing Docker 1.2.0 command-line calls are still using the array of key/values.

Docker-DCO-1.1-Signed-off-by: getvictor <victor@victoreda.com> (github: SvenDowideit)
Fix the other API docs to use an array of key/values

as per #7706

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Merge pull request #7735 from SvenDowideit/lxcconf-api-docs

Lxcconf api docs