Close inputstream of GridFSInputFile once chunk saved

Author: greenlaw110

src/main/com/mongodb/gridfs/GridFSInputFile.java

@@ -289,6 +289,11 @@ private void _finishData() {
             _messageDigester = null;
             _length = _totalBytes;
             _savedChunks = true;
+            try {
+                if (null != _in) _in.close();
+            } catch (IOException e) {
+                //ignore
+            }
         }
     }