Fix namespace filtering in ChangeHandler.

In addition to the actual fix (include/exclude params in the correct order),
thich change includes a number of improvements to debug logging and
error reporting during change handling on the client.

Note: this needs to be backported to the wmf12 branch.

Change-Id: Ib8ac99f762b9aed5f61d62c10bf7706ed70affa8
Merge "Fix namespace filtering in ChangeHandler."