Protocols.HTTP.Query: async request fails when keep-alive connection was closed
Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=7143
Reported by Martin Karlgren marty@roxen.com
If a Protocols.HTTP.Query instance is used with a keep-alive connection, async_request fails if the remote end closed the connection.
Proposed fix attached.