fix yamllint reported errors under roles/
    
    With the fix some warnings are still left...
    
        # yamllint -d "{extends: default, rules: {line-length: {max: 120}, indentation: disable}}"  roles/
        roles/standard-test-avocado/tasks/main.yml
        6:11      warning  too few spaces before comment  (comments)
    
        roles/standard-test-source/vars/main.yml
        6:10      warning  truthy value should be one of [false, true]  (truthy)
        7:13      warning  truthy value should be one of [false, true]  (truthy)
    
        roles/standard-test-source/tasks/main.yml
        13:21     warning  truthy value should be one of [false, true]  (truthy)
        34:21     warning  truthy value should be one of [false, true]  (truthy)
        38:20     warning  truthy value should be one of [false, true]  (truthy)
    
        roles/standard-test-beakerlib/tasks/main.yml
        39:12     warning  truthy value should be one of [false, true]  (truthy)
        48:12     warning  truthy value should be one of [false, true]  (truthy)
    
        roles/str-common-pkgs/tasks/pkgs-rpm-ostree.yml
        1:1       warning  missing document start "---"  (document-start)
        29:18     warning  truthy value should be one of [false, true]  (truthy)
        41:19     warning  truthy value should be one of [false, true]  (truthy)
        42:18     warning  truthy value should be one of [false, true]  (truthy)
        43:18     warning  truthy value should be one of [false, true]  (truthy)
    
        roles/str-common-pkgs/tasks/main.yml
        1:1       warning  missing document start "---"  (document-start)
    
        roles/str-common-pkgs/tasks/inspect.yml
        1:1       warning  missing document start "---"  (document-start)
        7:19      warning  truthy value should be one of [false, true]  (truthy)
        8:21      warning  truthy value should be one of [false, true]  (truthy)
        11:23     warning  truthy value should be one of [false, true]  (truthy)
        16:19     warning  truthy value should be one of [false, true]  (truthy)
    
        roles/str-common-pkgs/tasks/pkgs-yum.yml
        1:1       warning  missing document start "---"  (document-start)
        18:18     warning  truthy value should be one of [false, true]  (truthy)
    
        roles/str-common-pkgs/tasks/pkgs-dnf.yml
        1:1       warning  missing document start "---"  (document-start)
        25:18     warning  truthy value should be one of [false, true]  (truthy)
    
        roles/standard-test-basic/vars/main.yml
        2:1       warning  missing document start "---"  (document-start)
    
        roles/str-common-init/tasks/main.yml
        1:1       warning  missing document start "---"  (document-start)
    
        roles/str-common-init/tasks/inspect.yml
        1:1       warning  missing document start "---"  (document-start)
        7:19      warning  truthy value should be one of [false, true]  (truthy)
        8:21      warning  truthy value should be one of [false, true]  (truthy)
        11:23     warning  truthy value should be one of [false, true]  (truthy)
        16:19     warning  truthy value should be one of [false, true]  (truthy)
    
        roles/str-common-init/tasks/trunner.yml
        1:1       warning  missing document start "---"  (document-start)
        10:21     warning  truthy value should be one of [false, true]  (truthy)
        31:21     warning  truthy value should be one of [false, true]  (truthy)
        34:21     warning  truthy value should be one of [false, true]  (truthy)
        53:21     warning  truthy value should be one of [false, true]  (truthy)