only attempt to copy truststore if the cluster is secure
remove mapr-client install from mapr-hive.

mapr-hive will pull in mapr-core or, if mapr-client is already installed, it can use that.
let impala automatically pull in any dependencies.

If this fails, we are probably co-locating multiple versions of hive on the same node.
added python-lxml to prereqs

allows editing of hadoop properties files by the hadoop_properties module
move impala services

They do not want to overlap with hive .13, and I do not want to force hive .12 installs. Instead, separate them.
print MCS URLs for private IPs and ec2 public.
only create mount if the node is not an NFS server.
added a check for the impala role

before running the test, see if the node has the impala role