Eleven: Create one cursor per background task

If we call loadInBackground() twice we will have conflicts since
the two threads will share the cursor. The cursor is only used by
loadInBackground(), there's no need to have a class member for it,
so just keep it in a local variable to prevent conflicts.

BUGBASH-1045

Change-Id: Id484bee852d886c3a49ec8c84ef821f969db9a54