Update canvas.py

Added an IE_NAME and IE_DESC line to canvas.py so the supported sites would be correctly identified in https://github.com/rg3/youtube-dl/blob/master/docs/supportedsites.md

youtube_dl/extractor/canvas.py

@@ -7,6 +7,8 @@ from ..utils import float_or_none
 
 
 class CanvasIE(InfoExtractor):
+    IE_NAME = 'VRT'
+    IE_DESC = 'Een.be and Canvas.be'    
     _VALID_URL = r'https?://(?:www\.)?(?P<site_id>canvas|een)\.be/(?:[^/]+/)*(?P<id>[^/?#&]+)'
     _TESTS = [{
         'url': 'http://www.canvas.be/video/de-afspraak/najaar-2015/de-afspraak-veilt-voor-de-warmste-week',