Don't strip HTML attributes from inspected links

When you inspect a link, then close the inspector immediately,
nothing should change. However, AnnotationInspector was comparing
the generated annotation and the existing annotation by hash, and so
would consider an annotation with htmlAttributes different from
one without. This meant that inspecting a Parsoid-generated link
and then closing the inspector would cause a transaction to be
processed that removes the htmlAttributes from the annotation.

I believe a similar issue also existed for annotations with attributes
like origTitle and hrefPrefix, although I didn't reproduce this.

The fix is to have AnnotationInspector compare annotations by the
hash of their comparableObjects, rather than their hashObjects.

Change-Id: I848ffc2b7e7b2c67754a0ece3af105ffafa837ec
Merge "Don't strip HTML attributes from inspected links"