Fixed virtual switch interface_address and os_managed fields

The interface_address was being set every puppet run because the underlying interface can have two address (IPv6 and IPv4) and the user only specifies one of them, so it could happen sometimes that the one returned didn't match the one configured by the user. Now the address specified in the manifest is the one returned if it's bound to the virtual switch defined in the system.

The os_managed PS script was returning the string 'True' or 'False', now this value is checked in ruby to return proper boolean values.