Edited Issue: http_listener - doesn't report errors correctly after reading headers [220]

Taking a look at the code I think I can see this is an issue with the http_listener implementation. Basically it appears the problem is the listener implementation is NOT properly calling the _complete API in error cases after the HTT headers have been processed. For example in http_linux_server.cpp in the handle_body method if an error occurs we never actually end up calling _complete with an exception. There are several places where this is needed.

Affects Linux/OS X/iOS

Discovered when http_client cancellation functionality was implemented in this pull request:

https://casablanca.codeplex.com/SourceControl/network/forks/tsone/LinuxClientConnectionReuse/contribution/7093