test-reboot.yml: test.log is mandatory, improve results format
    
    According to
    https://docs.fedoraproject.org/en-US/ci/standard-test-interface/#_invocation
    every test must provide *test.log*.
    
    Improve *results.yml* format.
    
    Drop *avc.err.log* and log everything AVC denial related to *avc.log*