Dropping index that is being built doesn't cancel associated build query

-Start a long-running index creation

-Drop the index while it is still being built

-Notice that the query is still "active"

I would expect that the query would be stopped with an "error" state.  I haven't tested, but this should be treated the same as if an index node crashed during the index creation...might be a separate test case needed for that...how long should it take for the query to notice that the index is not avialable?