loading probe data fails when you yank a RAID member

[Michael Hudson-Doyle]

This happens when you yank the USB key that is part of an active RAID. I'm not sure this is a very realistic situation so perhaps we don't worry over much...

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: subiquity (not installed)
ProcVersionSignature: Ubuntu 5.3.0-19.20-generic 5.3.1
Uname: Linux 5.3.0-18-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu8.2
Architecture: amd64
CasperVersion: 1.429
CrashDB: {'impl': 'launchpad', 'project': 'subiquity'}
Date: Tue Nov 12 23:21:16 2019
ExecutablePath: /snap/subiquity/1329/usr/bin/subiquity
InstallationDate: Installed on 2019-08-30 (74 days ago)
InstallationMedia: Ubuntu-Server 19.10 "Eoan Ermine" - Alpha amd64 (20190829)
InterpreterPath: /snap/subiquity/1329/usr/bin/python3.6
LiveMediaBuild: Ubuntu-Server 20.04 LTS "Focal Fossa" - Alpha amd64 (20191105)
MachineType: Hewlett-Packard HP Compaq Elite 8300 SFF
ProcAttrCurrent: snap.subiquity.subiquity-service (complain)
ProcCmdline: /snap/subiquity/1329/usr/bin/python3 /snap/subiquity/1329/usr/bin/subiquity
ProcEnviron:
 TERM=linux
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
ProcKernelCmdLine: BOOT_IMAGE=/casper/vmlinuz quiet ---
Python3Details: /usr/bin/python3.7, Python 3.7.5rc1, python3-minimal, 3.7.5-1
PythonDetails: /usr/bin/python2.7, Python 2.7.17rc1, python-minimal, 2.7.17-1
SnapChannel: edge/mwhudson
SnapRevision: 1329
SnapVersion: 19.11.1+git1.73b53f2b
SourcePackage: subiquity
Title: loading probe data crashed with KeyError
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/16/2013
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: K01 v02.90
dmi.board.asset.tag: RBA20140586
dmi.board.name: 3397
dmi.board.vendor: Hewlett-Packard
dmi.chassis.asset.tag: RBA20140586
dmi.chassis.type: 4
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvrK01v02.90:bd07/16/2013:svnHewlett-Packard:pnHPCompaqElite8300SFF:pvr:rvnHewlett-Packard:rn3397:rvr:cvnHewlett-Packard:ct4:cvr:
dmi.product.family: 103C_53307F G=D
dmi.product.name: HP Compaq Elite 8300 SFF
dmi.product.sku: QV996AV
dmi.sys.vendor: Hewlett-Packard