ConfirmEdit uses MainStash as the backend to write its captchas. We
are migrating this extension to use the MicroStash store instead which
is more suitable.
This patch will store the captcha in MicroStash, read it from there
or fallback to MainStash if lookup was not successful. The code will
then clear both stores once after processing.
Migration plan
==============
step .1: Write to microstash store only, read from it or
fallback to mainstash store. Then delete from
both backends.
step .2: Read from microstash store only, delete from the
microstash store, and remove dead code afterward.
Bug: T336004
Change-Id: Ie7c50a6efe7a0aefc97a712b2ad961e7837cc4cf
This lays some groundwork for migrating from the main stash to a future
stash that resides in the primary datacenter.
Bug: T336004
Change-Id: I70ee88e9371af19890cb9e3da612d2bb7dc335e8