Negotiate vCD Version

Request highest supported vCD version between MON and
vCD on setup and then continue to use v27.0 as the confirmed
tested version.

BUG 775

Change-Id: I04333fa0c915107fb432d799d3440fec711d95ec
Signed-off-by: beierl <mbeierl@vmware.com>
(cherry picked from commit 7f8f8936)