Fixed variable name

Author: wiazur

samples/vision/content_moderator_image_moderation_samples.py

@@ -69,4 +69,4 @@ def image_moderation(subscription_key):
     import os.path
     sys.path.append(os.path.abspath(os.path.join(__file__, "..", "..")))
     from tools import execute_samples
-    execute_samples(globals(), SUBSCRIPTION_KEY_ENV_NAME)
+    execute_samples(globals(), SUBSCRIPTION_KEY)