gdbus crashed with segmentation fault

[Paul Menzel]

With (Dell) Ubuntu 20.04.1 on a Dell XPS 13 9310, after allowing release upgrades, the process crashed the first time.

```
$ sudo do-release-upgrade
Neue Veröffentlichungen von Ubuntu werden gesucht
Holen:1 Signatur der Aktualisierungsanwendung [819 B]
Holen:2 Aktualisierungsanwendung [1.338 kB]
Es wurden 1.339 kB in 0 s geholt (0 B/s)
»groovy.tar.gz« wird gegenüber »groovy.tar.gz.gpg« legitimiert
»groovy.tar.gz« wird entpackt

Zwischenspeicher wird gelesen
Speicherzugriffsfehler
```

```
$ dmesg
[…]
[42711.249670] gdbus[38237]: segfault at a0 ip 00007fb16b69f0cd sp 00007fb163ffea60 error 4 in libc-2.31.so[7fb16b67b000+178000]
[42711.249681] Code: fd ff 49 83 c5 02 41 0f b7 6d fe 49 89 c6 4c 8d 78 fe 4d 85 e4 75 13 eb cc 0f 1f 40 00 4c 8b 63 08 48 83 c3 08 4d 85 e4 74 bb <66> 41 3b 2c 24 75 ec 49 8d 7c 24 02 4c 89 fa 4c 89 ee e8 9c c4 fd
[…]
```

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubuntu-release-upgrader-core 1:20.04.28 [origin: unknown]
ProcVersionSignature: Ubuntu 5.6.0-1032.33-oem 5.6.19
Uname: Linux 5.6.0-1032-oem x86_64
ApportVersion: 2.20.11-0ubuntu27.10
Architecture: amd64
CasperMD5CheckResult: skip
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Tue Oct 27 10:45:53 2020
DistributionChannelDescriptor:
 # This is the distribution channel descriptor for the OEM CDs
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-focal-amd64-20200502-85
InstallationDate: Installed on 2020-10-16 (10 days ago)
InstallationMedia: Ubuntu 20.04 "Focal" - Build amd64 LIVE Binary 20200502-05:58
PackageArchitecture: all
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
Symptom: release-upgrade
UpgradeStatus: Upgraded to focal on 2020-10-27 (0 days ago)
VarLogDistupgradeAptlog:
 Log time: 2020-10-27 10:45:21.955323
 Log time: 2020-10-27 10:45:24.032294
modified.conffile..etc.update-manager.release-upgrades: [modified]
mtime.conffile..etc.update-manager.release-upgrades: 2020-10-27T10:40:13.677932