This change adds the search_all_by_tags_safe function, which
operaties exactly as search_all_by_tags but raises an exception
after the first page of data is returned, it the search resultset
size exceeds a specific threshold.
This enables better control over cases where a search query selects
too many records and cannot be fully served by NSX search.
Change-Id: I475377bd6f6a8e78a5a92c369d9d0e1c95ea4829
458234972d