Support Firefox 46-47 intermediate standard in Python lib as well

Author: marco-c

python/http_ece/__init__.py

@@ -67,8 +67,12 @@ def lengthPrefix(key):
         keyinfo = buildInfo(b"aesgcm", context)
         nonceinfo = buildInfo(b"nonce", context)
     elif padSize == 1:
-        keyinfo = b"Content-Encoding: aesgcm128"
-        nonceinfo = b"Content-Encoding: nonce"
+        if authSecret is not None:
+          keyinfo = buildInfo(b"aesgcm128", context)
+          nonceinfo = buildInfo(b"nonce", context)
+        else:
+          keyinfo = b"Content-Encoding: aesgcm128"
+          nonceinfo = b"Content-Encoding: nonce"
     else:
         raise Exception(u"unable to set context for padSize=" + str(padSize))