llapi: Fix read call on HTTPResponse

Back in Python 3.5.0, the HTTPResponse base class changed from RawIOBase to
BufferedIOBase, and the 'readall' method went away. 'read' should have always
been used, anyway.

scripts/lib/llapi.py

@@ -62,7 +62,7 @@ def _do_api_call(request_dict, json_response):
     if not json_response:
         return f
 
-    response = f.readall().decode('utf-8')
+    response = f.read().decode('utf-8')
     return json.loads(response, object_pairs_hook=OrderedDict)