Fix regression with attachment loading progress

* Oops!

Bug: 5375620
Change-Id: Ie890756c4c5d9fd970670007dcb0f38825eba23b
diff --git a/src/com/android/exchange/adapter/AttachmentLoader.java b/src/com/android/exchange/adapter/AttachmentLoader.java
index 1d79267..4370349 100644
--- a/src/com/android/exchange/adapter/AttachmentLoader.java
+++ b/src/com/android/exchange/adapter/AttachmentLoader.java
@@ -212,7 +212,7 @@
                             if (len != 0) {
                                 // len > 0 means that Content-Length was set in the headers
                                 // len < 0 means "chunked" transfer-encoding
-                                readChunked(is, os, len);
+                                readChunked(is, os, (len < 0) ? mAttachmentSize : len);
                                 finishLoadAttachment();
                                 return;
                             }