scripts: make sure that QEMU_TESTING_STATUS is always set to py.test exit status
scripts: make sure that QEMU_TESTING_STATUS is always set to py.test exit status

Changelog: none

Signed-off-by: Maciej Borzecki <f609d9f713abcd5f8f0e51f08dc151638a7681e7@rndity.com>

mendersoftware/meta-mender-qemu