JCBC-213: Implement better Exception names for CacheBucket

This changeset removes ambigous TODO exceptions and exchanges them
with proper ones.

Change-Id: Ic9b922a6007ad6979e890aab43b024bdd4ea5808
Reviewed-on: http://review.couchbase.org/24046
Tested-by: Michael Nitschinger <michael.nitschinger@couchbase.com>
Reviewed-by: Deepti Dawar <deepti.dawar@globallogic.com>
Tested-by: Deepti Dawar <deepti.dawar@globallogic.com>