Delete expired instance console auth tokens

Instance console auth tokens never get deleted from the cache
before the instnace is deleted, this is a waste of memory. now
we check if tokens are expired then remove them from the cache
before store new tokens.

Fix bug #1209134

Co-authored-by: Takashi Natsume <natsume.takashi@lab.ntt.co.jp>
Change-Id: I8dd5089ebaed3b3d91932f1f1558bbe302cd5675
Merge "Delete expired instance console auth tokens"