* api/complete-multipart: tests and simplification.
- Removing the logic of sending white space characters.
- Fix for incorrect HTTP response status for certain cases.
- Tests for New Multipart Upload and Complete Multipart Upload.
* tests: test for Delelete Object API handler
This function is added to extend the standard error responses.
Which is needed in some cases for example CompleteMultipartUpload
should respond with ErrPartTooSmall error when parts uploaded are
lesser than 5MB (i.e minimum allowed size per part).
Fixes#1536