Minor Quick Query update (#8523)

Author: seanmcc-msft

specification/storage/data-plane/Microsoft.BlobStorage/preview/2019-12-12/blob.json

@@ -9190,7 +9190,7 @@
           }
         },
         "HasHeaders": {
-          "type": "string",
+          "type": "boolean",
           "description": "has headers",
           "xml": {
             "name": "HasHeaders"