Correcting comment on isHDFSSelected method.
Handling case where serviceComponents.properties is null (ie: the stack def for the given service does not specify any properties).
Revert "Handling case where serviceComponents.properties is null (ie: the stack def for the given service does not specify any properties)."

This reverts commit c29b7ad4d5d5e2f799860532071b43616602f0a5.
Handling case where serviceComponents.properties is null.