Minor updates to OVSDB documents

Minor updates to OVSDB documents

- Replace two different links to RFC 7047 with a single link (as is, it
  sounds like "The Open vSwitch Database Management Protocol" is
different from RFC 7047, but it is the title.

- Replace non-working link to old version of OpenFlow 1.3 (v1.3.1) with
  good link to latest version (1.3.4).

- Replace ovs-vsdctl w/ovs-vsctl

- A couple of very minor edits.

- Addressed Sam's comments.

Change-Id: Ib202bf2d806cc8986040bac0eff68a7c9f6edf55
Signed-off-by: Andre Fredette <anfredette@gmail.com>