Removing unused variables, set filename correctly for logging

Context: SetVbucketState [couchKVStore]

Change-Id: I970233c41a551fc85eeaeac6d3c29f9cc2eef685
Reviewed-on: http://review.couchbase.org/43927
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: abhinav dangeti <abhinav@couchbase.com>