Refactor Request.createReadStream() implementation

Resolves behavioral change in Node.js v0.10.29 that caused
download failures when using streams over HTTPS.

Fixes #312

lib/request.js

@@ -517,7 +517,7 @@ AWS.Request = inherit({
 
     if (AWS.HttpClient.streamsApiVersion === 2) {
       stream = new streams.Readable();
-      stream._read = function() { stream.push(''); };
+      stream._read = function() {};
     } else {
       stream = new streams.Stream();
       stream.readable = true;
@@ -544,21 +544,27 @@ AWS.Request = inherit({
         });
 
         var httpStream = resp.httpResponse.stream;
-        stream.response = resp;
-        stream._read = function() {
-          var data;
-          do {
-            data = httpStream.read();
-            if (data) stream.push(data);
-          } while (data);
-          stream.push('');
-        };
-
-        var events = ['end', 'error', (legacyStreams ? 'data' : 'readable')];
-        AWS.util.arrayEach(events, function(event) {
-          httpStream.on(event, function(arg) {
-            stream.emit(event, arg);
+        if (legacyStreams) {
+          httpStream.on('data', function(arg) {
+            stream.emit('data', arg);
           });
+          httpStream.on('end', function() {
+            stream.emit('end');
+          });
+        } else {
+          httpStream.on('readable', function() {
+            while (null !== (chunk = httpStream.read())) {
+              stream.push(chunk);
+            }
+            stream.read(0);
+          });
+          httpStream.on('end', function() {
+            stream.push(null);
+          });
+        }
+
+        httpStream.on('error', function(err) {
+          stream.emit('error', err);
         });
       }
     });