add megaraid_physical_drives_{sata,sas} facts
change smartd.conf ERB to use megaraid_physical_drives_{sas,sata} facts

This modification add ssupport for polling the SMART values of SAS
drives behind a MegaRAID controller.  The `megaraid_physical_drives`
fact is no longer used internally by this module.
Merge pull request #22 from jhoblitt/feature/megaraid_facts

add megaraid_physical_drives_{sata,sas} facts