[ovs-dev] Introduce OVSDB readme markdown

[Ben Pfaff]

On Wed, Apr 13, 2016 at 12:00:01PM -0500, Ryan Moats wrote:
> From: RYAN D. MOATS <rmoats at us.ibm.com>
> 
> Provide a point to start collecting documentation on OVSDB
> and seed it with experiences from making use of change
> tracking.
> 
> Signed-off-by: RYAN D. MOATS <rmoats at us.ibm.com>

Needs to be added to EXTRA_DIST, otherwise it breaks the build:

    The following files are in git but not the distribution:
    ovsdb/README.md
    Makefile:5286: recipe for target 'dist-hook-git' failed

Do you think that it's better to put this in a separate file, or do you
think that it might be more useful in lib/ovsdb-idl.h?

Thanks,

Ben.