[Merge] ~aleasto/update-notifier:redirect-stderr into update-notifier:master

[Alessandro Astone]

The proposal to merge ~aleasto/update-notifier:redirect-stderr into update-notifier:master has been updated.

Commit message changed to:

apt-check: Do not print apt warnings to stderr

PRO_ESM_CACHE_DIR does not exist in non-LTS releases, and apt is printing
warnings about it missing when trying to build the ESM cache.

However apt-check is printing its results as two integers "X;Y" on stderr
which update-notifier tries to parse to get the updates status.
Printing warnings on stderr breaks the parsing, and update-notifier would
always think there are 0 updates.

Fortunately that does not seem to have a large impact because most of the
updates counting logic is actually dead code behind an always invisible
system tray entry (?)

For more details, see:
https://code.launchpad.net/~aleasto/update-notifier/+git/update-notifier/+merge/475789
-- 
Your team Ubuntu Core Development Team is requested to review the proposed merge of ~aleasto/update-notifier:redirect-stderr into update-notifier:master.