[vulture] Remove the extractor

The first 10 URLs in google search "site:http://video.vulture.com/video"
is dead. I guess Vulture does not host videos on their own anymore.

youtube_dl/extractor/extractors.py

@@ -958,7 +958,6 @@ from .vporn import VpornIE
 from .vrt import VRTIE
 from .vube import VubeIE
 from .vuclip import VuClipIE
-from .vulture import VultureIE
 from .walla import WallaIE
 from .washingtonpost import (
     WashingtonPostIE,