Fix: Do not use readfp()

[pauliusm]

This fixes errors:

File ...hpilo_fw.py, line 32, in config
    parser.readfp(io.StringIO(conf))
    ^^^^^^^^^^^^^
AttributeError: 'ConfigParser' object has no attribute 'readfp'. Did you mean: 'read'?

because ConfigParser's readfp() is deprecated.