Don't ignore 400 errors when creating ES indices

It can reveal tricky issues, and ignoring the error is not going
to help anyway if the index has not been created when we blindly
expect it to present later.

src/olympia/lib/es/utils.py

@@ -102,6 +102,6 @@ def create_index(index, config=None):
     })
 
     if not es.indices.exists(index):
-        es.indices.create(index, body=config, ignore=400)
+        es.indices.create(index, body=config)
 
     return index