qa/check.callback.sample: check if pre-run AVC file exists before diff
qa/check.callback.sample: check if pre-run AVC file exists before diff

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp