ganeti.http: Remove _HttpClientError

This is a leftover from old code.

Reviewed-by: iustinp

lib/http/__init__.py

@@ -72,6 +72,7 @@ _SSL_UNEXPECTED_EOF = "Unexpected EOF"
 # send/receive quantum
 SOCK_BUF_SIZE = 32768
 
+
 class HttpError(Exception):
   """Internal exception for HTTP errors.
 
@@ -80,14 +81,6 @@ class HttpError(Exception):
   """
 
 
-class _HttpClientError(Exception):
-  """Internal exception for HTTP client errors.
-
-  This should only be used for internal error reporting.
-
-  """
-
-
 class HttpSocketTimeout(Exception):
   """Internal exception for socket timeouts.