ACCUMULO-3340 Restrict ZooKeeper binding in MAC

  Forces ZooKeeper to bind only to 127.0.0.1 in MiniAccumuloCluster,
  instead of the default, which is to bind to all interfaces.
Merge branch '1.5' into 1.6

Conflicts:
	minicluster/src/main/java/org/apache/accumulo/minicluster/MiniAccumuloCluster.java