FAB-15313 Consensus migration: polish main_test
FAB-15313 Consensus migration: polish main_test

Polish main_test.go, as suggested in review comments of:
FAB-15174 Consensus migration: server boot sequence

Change-Id: I70e9bd01c7c97e571a83fe599a75431fb47e62c7
Signed-off-by: Yoav Tock <618f5b57a756fd7973a0b7f687acf4b909eff682@il.ibm.com>

manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,manish-sethi/fabric-sidedb,muralisrini/fabric,manish-sethi/fabric-sidedb,manish-sethi/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,manish-sethi/fabric,hyperledger/fabric,binhn/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,muralisrini/fabric,binhn/fabric,jimthematrix/fabric,muralisrini/fabric,hyperledger/fabric,binhn/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,jimthematrix/fabric