HTTP redirection does not handle correctly locations with url-encoded content

[Oldes]

Example is reading release files from GitHub:

>>  read https://github.com/upx/upx/releases/download/v3.96/upx-3.96-win32.zip
...
    Location: {https://github-releases.githubusercontent.com/67031040/2f297180-3d73-11ea-81eb-e3192446510e?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20210304%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20210304T095933Z&X-Amz-Expires=300&X-Amz-Signature=daef518d6ed958abf0892144b2232041583129ef451be0f6e55f5ff5deafb3fb&X-Amz-SignedHeaders=host&actor_id=0&key_id=0&repo_id=67031040&response-content-disposition=attachment%3B%20filename%3Dupx-3.96-win32.zip&response-content-type=application%2Foctet-stream}
...
 [HTTP] Redirect to: https://github-releases.githubusercontent.com/67031040/2f297180-3d73-11ea-81eb-e3192446510e?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%252F20210304%252Fus-east-1%252Fs3%252Faws4_request&X-Amz-Date=20210304T095933Z&X-Amz-Expires=300&X-Amz-Signature=daef518d6ed958abf0892144b2232041583129ef451be0f6e55f5ff5deafb3fb&X-Amz-SignedHeaders=host&actor_id=0&key_id=0&repo_id=67031040&response-content-disposition=attachment%253B%2520filename%253Dupx-3.96-win32.zip&response-content-type=application%252Foctet-stream
...
** Access error: protocol error: "Server error: HTTP/1.1 400 Bad Request"

Notice that for example: application%2Foctet-stream from the location is converted to: application%252Foctet-stream, which is cause of the problem!

[Oldes]

The commit above fixed the issue, but I'm not sure, if there it would not cause problems elsewhere... there should be more extensive HTTP tests... but not at this moment.