Bugfix to SelectiveSerializer.

Commit 6d704298f8953950beb3c0aee81e3e9803e36149 introduced a few bugs
because I didn't realize that the callbacks took two parameters; the
first was supposed to be an 'error' object. (I also missed a 'this.'
in one instance.)  Squash the bugs.

Change-Id: I45f9874d2000e8d8bc5c64cec08e9fbd90e77668
Merge "Bugfix to SelectiveSerializer."