openbmctool: firmware list fails with unactivated image

[spinler]

For an unactivated image like:

"/xyz/openbmc_project/software/ace821ef": {
      "Activation": "xyz.openbmc_project.Software.Activation.Activations.Ready",
      "ExtendedVersion": "op-build-v2.0.10-24-g6c8e467,buildroot-2018.05.1-9-gc99f2ee,skiboot-v6.0.14,hostboot-3bf7fcf-pf177c86,occ-3a505ff,linux-4.17.12-openpower1-pfd19258,petitboot-v1.7.3-pe15f91f,machine-xml-dce824c,hostboot-binaries-hw112718a.op920,capp-ucode-p9-dd2-v4,sbe-7aa21f6,hcode-hw112718a.op920",
      "Path": "/tmp/images/ace821ef",
      "Purpose": "xyz.openbmc_project.Software.Version.VersionPurpose.Host",
      "RequestedActivation": "xyz.openbmc_project.Software.Activation.RequestedActivations.None",
      "Version": "IBM-witherspoon-OP9-v2.0.10-2.22",
      "associations": [
        [
          "inventory",
          "activation",
          "/xyz/openbmc_project/inventory/system/chassis"
        ]
      ]
    },

openbmctool firmware list will fail like:

./openbmctool.py -U root -P 0penBmc -H $BMC firmware list
Attempting login...
Traceback (most recent call last):
  File "./openbmctool.py", line 3772, in <module>
    main()
  File "./openbmctool.py", line 3745, in main
    output = args.func(args.host, args, mysess)
  File "./openbmctool.py", line 2061, in firmwareList
    firmwareInfoDict = parseFWdata(firmwareDict)
  File "./openbmctool.py", line 1995, in parseFWdata
    if firmwareDict['data'][key]['Priority'] == 0:
KeyError: 'Priority'