doc: fix typos in http.markdown
doc: fix typos in http.markdown

PR-URL: https://github.com/joyent/node/pull/4784
Reviewed-by: Chris Dickinson <38a75c4c4f5646d63b752460df745c5b937b7e58@gmail.com>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node