Refactor XML handling of select_object_content() API

[balamurugana]

No description provided.

[BigUstad]

The object used in the call exists in s3. It is also copied to the locally running minio server.
For the ame object in s3, minio; minio downloads the file correctly but s3 doesn't..
And examples/select_object_content.py

client = Minio('s3.amazonaws.com', access_key='<ACCESS_KEY_VALUE>', secret_key='<SECRET_KEY_VALUE>')

For locally running minio server.
client = Minio('192.168.1.2:9000', access_key='<ACCESS_KEY_VALUE>', secret_key='<SECRET_KEY_VALUE>', secure=False)

Trace (requests only)
GET /pribkt3?location= HTTP/1.1
Host: 192.168.1.2:9000
User-Agent: MinIO (Darwin; x86_64) minio-py/7.0.0
X-Amz-Content-Sha256:
X-Amz-Date: 20201015T212037Z
Authorization: AWS4-HMAC-SHA256 Credential=REDACTED/20201015/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date, Signature=REDACTED

GET /?location= HTTP/1.1
Host: amazonaws.com
User-Agent: MinIO (Darwin; x86_64) minio-py/7.0.0
X-Amz-Content-Sha256: UNSIGNED-PAYLOAD
X-Amz-Date: 20201015T212037Z
Authorization: AWS4-HMAC-SHA256 Credential=REDACTED/20201015/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date, Signature=REDACTED

which results in this error:

Traceback (most recent call last): File "examples/select_object_content.py", line 57, in <module> data = client.select_object_content('pribkt3', 'samplecsvdata/archive/TotalPopulationByGender.csv.gz', request) <Trace...> minio.error.S3Error: S3 operation failed; code: AllAccessDisabled, message: All access to this object has been disabled, resource: None, request_id: AE024B3CFA45B583, host_id:<value>

[BigUstad]

Please look exceptions of client with s3 server.

[balamurugana]

Please look exceptions of client with s3 server.

Please use the fix #1004

[ebozduman]

LGTM

[kannappanr]

LGTM