http_server: fix resume after socket close
Socket resume may happen on a next tick, and in following scenario:
socket.resume()
socket._handle.close()
socket._handle = null;
The _resume
will be invoked with empty ._handle
property. There is
nothing bad about it, and we should just ignore the resume
/pause
events in this case.
Same applies to the unconsuming of socket on adding data
and/or
readable
event listeners.