ovs-vswitchd: Document the '--unixctl' option.

The option is documented for ovsdb-server but not for ovs-vswitchd.
This commit adds the documentation for ovs-vswitchd too.

Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>
Acked-by: Alex Wang <alexw@nicira.com>
ovs-vswitchd: Add a missing headline in documentation.

The logging options were shown as part of the "Public Key Infrastructure
Options". Correct it.

Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>
Acked-by: Alex Wang <alexw@nicira.com>