package resolvconf 1.79ubuntu10 failed to install/upgrade: installed resolvconf package post-installation script subprocess returned error exit status 1

During a "do-release-upgrade -d" from 16.04 to 18.04, an unrelated error occurred. DNS didn't work at that time, so I removed resolvconf. I manually updated my sources.list and did a successful dist-upgrade. Then I tried to reinstall resolvconf, and got the error below.

Installing new version of config file /etc/resolvconf/resolv.conf.d/head ...
Created symlink /etc/systemd/system/systemd-resolved.service.wants/resolvconf-pull-resolved.path → /lib/systemd/system/resolvconf-pull-resolved.path.
resolvconf-pull-resolved.service is a disabled or a static unit, not starting it.
resolvconf-pull-resolved.service is a disabled or a static unit, not starting it.
Removing obsolete conffile /etc/init/resolvconf.conf ...
cp: not writing through dangling symlink '/etc/resolvconf/resolv.conf.d/original'
dpkg: error processing package resolvconf (--configure):
 installed resolvconf package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 resolvconf
E: Sub-process /usr/bin/dpkg returned an error code (1)

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: resolvconf 1.79ubuntu10
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
AptOrdering:
 resolvconf:amd64: Install
 NULL: ConfigurePending
Architecture: amd64
Date: Fri May 4 11:46:44 2018
DuplicateSignature:
 package:resolvconf:1.79ubuntu10
 Removing obsolete conffile /etc/init/resolvconf.conf ...
 cp: not writing through dangling symlink '/etc/resolvconf/resolv.conf.d/original'
 dpkg: error processing package resolvconf (--configure):
  installed resolvconf package post-installation script subprocess returned error exit status 1
ErrorMessage: installed resolvconf package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2017-05-26 (343 days ago)
InstallationMedia: Ubuntu 16.04.2 LTS "Xenial Xerus" - Release amd64 (20170215.2)
PackageArchitecture: all
Python3Details: /usr/bin/python3.6, Python 3.6.5, python3-minimal, 3.6.5-3
PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1
RelatedPackageVersions:
 dpkg 1.19.0.5ubuntu2
 apt 1.6.1
SourcePackage: resolvconf
Title: package resolvconf 1.79ubuntu10 failed to install/upgrade: installed resolvconf package post-installation script subprocess returned error exit status 1
UpgradeStatus: Upgraded to bionic on 2018-05-04 (0 days ago)