-o option can't parse `release_date`, `upload_date` and `ext`

[laurencedev]

Reproduction:

The following command in a cmd on a Windows 10 Pro machine:

C:\Users\u\Videos>youtube-dl https://www.youtube.com/watch?v=D1ZYhVpdXbQ -o "%(playlist)s/%(playlist_index)s-%(title)s.%(release_date).%(ext)s"

would outputs:

[youtube] D1ZYhVpdXbQ: Downloading webpage
[youtube] D1ZYhVpdXbQ: Downloading video info webpage
[youtube] D1ZYhVpdXbQ: Downloading js player vflkUTZn2
[download] Destination: NA\NA-Singing In The Rain - Singing In The Rain (Gene Kelly) [HD Widescreen].%(ext)s
[download]   0.9% of 46.43MiB at 123.52KiB/s ETA 06:21

No ext value and release_date value parsed in the output's file name.

youtube-dl version: 2018.09.18

[dstftw]

Invalid output template. Must be %(release_date)s not %(release_date).