When growing chain only grow the chain. This addresses a NoSuchElementException.

Case:
Create bucket with timeout 5 seconds
add an element
wait more than 5 seconds
add a new element
  -- remove elements exceeding timeout this reduces buckets to 0 length via call to compact chain
  -- may be grow will create a new bucket to add the element
     -- next invocation of compact will removed the expired bucket

NB: There has to be a way to make this code simpler, however I am leaving this as it is for now