versionutils.is_compatible calling unnecessary tuple conversion

[chenyujie]

Code abstract as following:

def is_compatible(requested_version, current_version, same_major=True):
...
    if same_major and (requested_parts[0] != current_parts[0]):
        return False

    return current_parts >= requested_parts
...

'requested_parts' can be compared with 'current_parts' without using tuple reference, such as:

    if same_major and (requested_parts != current_parts):
        return False

Otherwise it would cause a warning from 'pkg_resources'.

[ChangBo Guo(gcb) (glongwave)]

This is duplicated with https://bugs.launchpad.net/oslo.utils/+bug/1706394 and fixed