zookeeper group doesn't exisit in centos, but it should according to the init.d script, so we'll add it
zookeeper group doesn't exisit in centos, but it should according to the init.d script, so we'll add it

stackdio-formulas/hdp2-formula,clarkperkins/hdp2-formula,stackdio-formulas/hdp2-formula,clarkperkins/hdp2-formula