upgrade.sh v4.6.5: Refined logic and doc for 'to-or-thru' 2019.1 upgrades.
The logic to implicitly disable online upgrades for 'to-or-thru'
P4D 2019.1 upgrades now only applies if not on the master server.
The master server will still be started after unless the '-M'
option is used to specifically request a manual upgrade option.