fix: read a Supermicro X10 with only the OOB license over Redfish (0.3.1)

First run against real hardware over Redfish: an X10DRL-i (BMC 3.91) with
SFT-OOB-LIC. Its Redfish tree is recorded under
tests/fixtures/supermicro-x10drl-i-3.91/redfish, scrubbed.

- A resource refused for want of a further license (403 OemLicenseNotPassed)
  no longer fails the getter. Storage then falls back to SimpleStorage. The
  firmware list falls back to the BMC and BIOS versions when UpdateService
  is withheld.
- get_device_warnings reports bmc_license_partial with the licenses and the
  withheld parts (drives, firmware inventory).
- A placeholder system model ("Super Server") is replaced by the board
  (PartNumber, else the chassis model).

tests/fixtures/supermicro-x10drl-i-3.91/redfish/Managers/1/FanMode/index.json

@@ -0,0 +1,14 @@
+{
+ "@odata.context": "/redfish/v1/$metadata#FanMode.FanMode",
+ "@odata.id": "/redfish/v1/Managers/1/FanMode",
+ "@odata.type": "#FanMode.v1_0_0.FanMode",
+ "Id": "Fan Mode",
+ "Mode": "Optimal",
+ "Mode@Redfish.AllowableValues": [
+  "Standard",
+  "FullSpeed",
+  "Optimal",
+  "HeavyIO"
+ ],
+ "Name": "FanMode"
+}