Fix traceback in old mirror counting program.
    
    When a corrupt date is found in the log file, I have the program
    default of 1970-01-01 but because there is a lookup used it needed to
    be 1970-Jan-01 which would then get replaced by 1970-01-01.
    
    Signed-off-by: Stephen Smoogen <ssmoogen@redhat.com>