Fix other flake8 complaints
    
    E231 missing whitespace after ','
    E265 block comment should start with '# '
    E266 too many leading '#' for block comment
    E302 expected 2 blank lines, found 1
    E501 line too long (115 > 88 characters)
    E713 test for membership should be 'not in'
    E722 do not use bare 'except'
    F812 list comprehension redefines 'g' from line 1499
    F821 undefined name 'cmp'
    F841 local variable 'ex' is assigned to but never used
    
    JIRA: COMPOSE-4108
    Signed-off-by: Haibo Lin <hlin@redhat.com>