HDFS-447: HDFS preInstallNotes: use the exact "in preview" sentence (#829)
HDFS-447: HDFS preInstallNotes: use the exact "in preview" sentence (#829)

* Use the exact "in preview" phrase

* Make it exactly as in https://jira.mesosphere.com/browse/DCOS-14968

mesosphere/dcos-commons,vishnu2kmohan/dcos-commons,vishnu2kmohan/dcos-commons,vishnu2kmohan/dcos-commons,vishnu2kmohan/dcos-commons,mesosphere/dcos-commons,vishnu2kmohan/dcos-commons,mesosphere/dcos-commons,mesosphere/dcos-commons,mesosphere/dcos-commons