Description
When running on a slow host (docker ubuntu on mac) the "sleep(3)" in tests/zkServer.sh is not sufficient wait for the server to enter RO mode. Recommend adding a "isro" 4lw check in the script to wait until the server is in RO mode. If this takes longer than 60 seconds the zkServer.sh should fail.
For more background see the comment here:
https://github.com/apache/zookeeper/pull/522#issuecomment-392980087