Fix CONTENT_TYPE and CONTENT_LENGTH handling

Fixes #15

Author: fbbdev

lib/request.js

@@ -122,7 +122,12 @@ Request.prototype._createReqRes = function () {
 
     for (var param in this.params) {
         if (HEADER_EXPR.test(param) || param === 'CONTENT_LENGTH' || param === 'CONTENT_TYPE') {
-            var name = param.slice(5).replace(UNDERSCORE_EXPR, '-');
+            var name = param.replace(HEADER_EXPR, '').replace(UNDERSCORE_EXPR, '-');
+
+            // Ignore HTTP_CONTENT_TYPE and HTTP_CONTENT_LENGTH
+            if (HEADER_EXPR.test(param) && (name.toLowerCase() === 'content-type' || name.toLowerCase() === 'content-length'))
+                continue;
+
             var value = this.params[param];
             raw.push(name, value);
             this._req._addHeaderLine(name, value, dest);