In case the hash grow failed, it is not fair to return error -
the new node _was_ _actually_ added in this case.

Besides, after my previous patch, this grow is more likely
to fail on large hashes.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>