Properly manage lifecycle of suggestion cursor

JoinContactLoader loads two cursor in a single load, which is doable,
but not in the way the old code did.

We need to tie the second cursor to the primary cursor in order to
have the framework manage its lifecycle properly.

Bug 6216651

Change-Id: Ia25431832a5b8b94bfd1b319e3d2d4533a4d3840