http: Hush 'MUST NOT have a body' warnings to debug()

lib/http.js

@@ -705,8 +705,8 @@ OutgoingMessage.prototype.write = function(chunk, encoding) {
   }
 
   if (!this._hasBody) {
-    console.error('This type of response MUST NOT have a body. ' +
-                  'Ignoring write() calls.');
+    debug('This type of response MUST NOT have a body. ' +
+          'Ignoring write() calls.');
     return true;
   }
 
@@ -767,8 +767,8 @@ OutgoingMessage.prototype.end = function(data, encoding) {
   }
 
   if (data && !this._hasBody) {
-    console.error('This type of response MUST NOT have a body. ' +
-                  'Ignoring data passed to end().');
+    debug('This type of response MUST NOT have a body. ' +
+          'Ignoring data passed to end().');
     data = false;
   }