Revert "Normalize HTTP headers."

This reverts commit f623fd7658.
But only the changes made in lib/ they were falsely detecting outgoing
headers.

lib/http.js

@@ -109,8 +109,11 @@ exports.parseUri.options = {
 };
 
 
+var connection_expression = /Connection/i;
+var transfer_encoding_expression = /Transfer-Encoding/i;
 var close_expression = /close/i;
 var chunk_expression = /chunk/i;
+var content_length_expression = /Content-Length/i;
 
 
 /* Abstract base class for ServerRequest and ClientResponse. */
@@ -244,15 +247,15 @@ OutgoingMessage.prototype.sendHeaderLines = function (first_line, headers) {
 
     message_header += field + ": " + value + CRLF;
 
-    if ("connection" === field) {
+    if (connection_expression.exec(field)) {
       sent_connection_header = true;
       if (close_expression.exec(value)) this.closeOnFinish = true;
 
-    } else if ("transfer-encoding" === field) {
+    } else if (transfer_encoding_expression.exec(field)) {
       sent_transfer_encoding_header = true;
       if (chunk_expression.exec(value)) this.chunked_encoding = true;
 
-    } else if ("content-length" === field) {
+    } else if (content_length_expression.exec(field)) {
       sent_content_length_header = true;
 
     }