fix url link

Author: PatrickFarley

articles/cognitive-services/Computer-vision/QuickStarts/python-analyze.md

@@ -61,7 +61,7 @@ else:
 if 'COMPUTER_VISION_ENDPOINT' in os.environ:
     endpoint = os.environ['COMPUTER_VISION_ENDPOINT']
 
-analyze_url = endpoint + "/vision/v2.1/analyze"
+analyze_url = endpoint + "vision/v2.1/analyze"
 
 # Set image_url to the URL of an image that you want to analyze.
 image_url = "https://upload.wikimedia.org/wikipedia/commons/thumb/1/12/" + \