Revert "inets: properly stop httpc_handler when send errors because of a closed connection"

This reverts commit 6b3bd0c5740e81f40a94d48abfc2ac2e55a76360.
inets: stop httpc_handler on 'connection closed' send error

httpc_handler should be stopped when sending requests returns error
because of a closed connection and `tcp_closed` message could not be
catched (see http://erlang.org/pipermail/erlang-bugs/2007-May/000346.html )
otherwise it will lead to process leak.