Chunked Content PUT requests do not clear 'HTTP_TRANSFER_ENCODING' key

Chunked Content PUT requests do not clear 'HTTP_TRANSFER_ENCODING' key

I discovered this when using waitress to wrap wsgidav.  What happens is that waitress correctly handles chunked file uploads from Mac Finder WebDAV clients by converting them to standard PUT requests ala Apache.  Unfortunately, waitress neglects to remove the 'HTTP_TRANSFER_ENCODING': 'chunked' key from the request.  So, wsgidav attempts to process the data as a chunked content upload.  The thing is, waitress already processed the chunked upload and bad things happen.

Removing the 'chunked' header allows for correct operation.