ci_fairy: Include commit SHA in junit error

It is already included in the testsuite name, but that isn't shown
in gitlab's UI, with the result that the front-page error report
is often useless and the user has to check out the pipeline logs.

Signed-off-by: Florian Müllner <fmuellner@gnome.org>
10 jobs for master in 2 minutes and 34 seconds (queued for 6 seconds)
Child pipeline (parent)
Status Job ID Name Coverage
  Centos Container Build
passed #7645209
centos:7@container-build@x86_64

00:01:40

passed #7645217
centos:8@container-build@x86_64

00:01:29

passed #7645212
centos@cache-container-build@x86_64

00:01:53

 
  Centos Check
passed #7645224
centos:7@base-image@x86_64

00:00:53

passed #7645219
centos:7@check@x86_64

00:00:27

passed #7645252
centos:8@check@x86_64

00:00:13

passed #7645232
centos@cache-check@x86_64

00:00:09

passed #7645243
check labels centos@x86_64:7

00:00:11

passed #7645239
do not rebuild centos:7@container-build@x86_64

00:00:30

passed #7645247
pull upstream centos:7@container-build@x86_64

00:00:40