Re: [PATCH] mergetool: Suppress stderr and fix the "both added" test

David Aguilar [off-list ref] writes:

Silence error messages when "git checkout-index" is used to
checkout a stage that does not exist.  This can happen now that
mergetool calls checkout_staged_file() unconditionally when
creating the temporary $BASE, $LOCAL, and $REMOTE files.

Fix the test so that it checks the contents of the "both added"
file.  The test was passing as a consequence of accidentally
handing a bad path to "cat".

Signed-off-by: David Aguilar <redacted>
---
This applies on top of da/maint-mergetool-twoway in pu.

Thanks.

It might make sense to squash this into the previous patch, which luckily
hasn't hit 'next' yet, though---which I can do locally without need for
re-send if you like.