inconsistent positional arguments in InternalClient

[clayg]

The signature for InternalClient get_object and a few others is reasonable:

    def get_object(self, account, container, obj, headers,
                   acceptable_statuses=(2,)):

    def iter_object_lines(
            self, account, container, obj, headers=None,
            acceptable_statuses=(2,)):

    def create_container(
            self, account, container, headers=None, acceptable_statuses=(2,)):

the pattern is (self, *aco, headers, acceptable_statuses)

the set_*_metadata method introduces a new concept of questionable utility:

    def set_container_metadata(
            self, account, container, metadata, metadata_prefix='',
            acceptable_statuses=(2,)):

    def set_object_metadata(
            self, account, container, obj, metadata,
            metadata_prefix='', acceptable_statuses=(2,)):

But still, with the default metadata_prefix='', the implementation ends up following the "normal" signature (i.e. the metadata arg ends up being just headers sent along with the request)

This IMHO makes get_object_metadata stick out like a sore thumb:

    def get_object_metadata(
            self, account, container, obj, metadata_prefix='',
            acceptable_statuses=(2,), headers=None):

And indeed calling it like get_object, i.e.

  my_internal_client.get_object_metadata('a', 'c', 'o', {'my-headers-are-important': True})

Does in fact smash your thumb with hammer.