Thunderbird and UPDATING 20170302

[Andriy Gapon]

FWIW, the following "hack" allowed me to keep my current profile and re-enabled
lightning in it.

First, I removed the addon before upgrading thunderbird.  Not sure if this was a
requirement.

After upgrading thunderbird and mucking with it for some time I did the following.
Shut down thunderbird.
Backed up ~/.thunderbird/<profile>/prefs.js file.
Opened the file in editor.
Found lines with extensions.lastAppVersion and extensions.lastPlatformVersion,
and "downgraded" thunderbird version in them (changed 45.7.1 to 45.7.0).
Removed line with
extensions.installedDistroAddon.{e2fda1a4-762b-4020-b5ad-a41df1933103} in it.
Restarted thunderbird.  And lightning was back.

Not sure if the above steps are sufficient.  Perhaps something in what I
described as 'mucking' was required too.

-- 
Andriy Gapon