[ixpmanager] Upgrade From v3

[Nick Hilliard]

Mike Hammett wrote on 29/06/2018 22:14:
> For one of our IXes, we started with v4 and used the install script to 
> do that. I liked the script because it presented fewer chances of me 
> screwing it up. The v3 upgrade instructions seem to have us building the 
> v4 environment from scratch. I just want to make sure that's accurate 
> before proceeding.

yes, that's accurate if you're upgrading from v3.  The further along the 
4.x branch things proceed, the more you need to build from scratch. You 
need to follow all the release notes for all the 4.x branch releases 
because there were some substantial changes along the way.

Nick