The `set -u` options in these scripts caused them to fail with 'unbound
variable' errors when CLI args or env variables were unset. This commit
fixes the validation so that the scripts output usage info or helpful
errors instead of exiting with unbound variable errors that the user
must read the source to diagnose.
for the script `ethereum/sh/upgrade_all_testnet.sh`, the commit updates
a variable name that appears incorrect.
John Saigle
heyitaki
Csongor Kiss