This change isolates the most common case (e.g. successful lookup)
from more complicates scenarios. It also (tries to) make code
more simple by avoiding retry: cycle.

The actual goal is to prepare code to the upcoming change that will
allow LL address retrieval without acquiring LLE lock at all.

Side effects:
Most of the change is just loop unrolling (e.g. splitting first iteration
from second one). However, in cases when we don't have LLE at all
we will do 2 LLE lookups instead of one. Since this situation should be rare
and in general lookups are fast I don't think there is a problem here.