Updates for DE18, remove text suggesting that netapp_server_port is a re...

...quired option.

TA229 for DE18 reads: Document needs to mention that netapp_transport_type and netapp_server_port are no longer mandatory options for iscsi and nfs drivers. They default to http and 80 respectively.

The current version of the Guide already states that *netapp_transport_type* and *netapp_server_type* are **optional** options and that they default appropriately.  This change removes several places where examples still set these options, unnecessarily, and perhaps confusingly since the other options set in these contexts are  required.