Minor Description
Currently zkcli does not allow passing arbitrary java system properties (e.g. java.io.tmpdir). It only supports configuring ZK ACLs via SOLR_ZK_CREDS_AND_ACLS environment variable. While we can overload SOLR_ZK_CREDS_AND_ACLS with additional parameters, it seems unclean. This jira is to add another environment variable to pass these parameters.
