Correct mock bucketfs upload method

[umitbuyuksahin]

Background

• An infinite loop occurs, while reading a file object chunk by chunk in the line shown below.
• The reason of the infinite loop is that the senitel character of the iter method is not correct. It should be b'', instead of ' '.

https://github.com/exasol/bucketfs-utils-python/blob/7ac95f606d3082e5fa1b4136be748732e20de713/exasol_bucketfs_utils_python/localfs_mock_bucketfs_location.py#L57

Acceptance Criteria

• Fixed the error
• Add unit tests regarding this method

[tkilias]

Do you mean b'' or b' '?

[umitbuyuksahin]

it is a typo, it must be b''