package shim-signed 1.17~15.10.1+0.8-0ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

Installer failed to recognize that /boot/efi needs to be remounted rw before being written to.

ProblemType: Package
DistroRelease: Ubuntu 15.10
Package: shim-signed 1.17~15.10.1+0.8-0ubuntu2
ProcVersionSignature: Ubuntu 4.2.0-42.49-generic 4.2.8-ckt12
Uname: Linux 4.2.0-42-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
BootEFIContents:
 grub.cfg
 grub.cfg,v
 grubx64.efi
 MokManager.efi
 shimx64.efi
Date: Mon Jul 11 17:03:32 2016
DuplicateSignature: package:shim-signed:1.17~15.10.1+0.8-0ubuntu2:subprocess installed post-installation script returned error exit status 1
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2016-03-10 (123 days ago)
InstallationMedia: Ubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
RelatedPackageVersions:
 dpkg 1.18.2ubuntu5.1
 apt 1.0.10.2ubuntu3
SourcePackage: shim-signed
Title: package shim-signed 1.17~15.10.1+0.8-0ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to wily on 2016-04-25 (77 days ago)