Comment 19 for bug 1538438

Martin Pitt, thanks for working on this. I've utilized the non-Proposed release and this worked fine. However, I'll leave it to others to certify this is passed/failed as the issue appears environment or timing specific.

sudo apt -y install flashplugin-installer
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
  x-ttcidfont-conf ttf-bitstream-vera | ttf-dejavu ttf-xfree86-nonfree
  xfs
The following NEW packages will be installed:
  flashplugin-installer
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/6,838 B of archives.
After this operation, 58.4 kB of additional disk space will be used.
Preconfiguring packages ...
Selecting previously unselected package flashplugin-installer.
(Reading database ... 280227 files and directories currently installed.)
Preparing to unpack .../flashplugin-installer_11.2.202.621ubuntu0.16.04.1_amd64.deb ...
Unpacking flashplugin-installer (11.2.202.621ubuntu0.16.04.1) ...
Processing triggers for update-notifier-common (3.168) ...
flashplugin-installer: downloading http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20160512.1.orig.tar.gz
Get:1 http://archive.canonical.com/pool/partner/a/adobe-flashplugin/adobe-flashplugin_20160512.1.orig.tar.gz [27.1 MB]
Fetched 27.1 MB in 1min 14s (362 kB/s)
W: Can't drop privileges for downloading as file '/var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20160512.1.orig.tar.gz' couldn't be accessed by user '_apt'. - pkgAcquire::Run (13: Permission denied)
Installing from local file /var/lib/update-notifier/package-data-downloads/partial/adobe-flashplugin_20160512.1.orig.tar.gz
Flash Plugin installed.
Setting up flashplugin-installer (11.2.202.621ubuntu0.16.04.1) ...

apt-cache policy apt
apt:
  Installed: 1.2.10ubuntu1
  Candidate: 1.2.10ubuntu1
  Version table:
 *** 1.2.10ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
        100 /var/lib/dpkg/status