Fix few dialyzer failures

Found few missed out incorrect specs which dialyzer
did not detect earlier before upr branch merge to master.

Change-Id: Ie08b5689b3c10b2a404058febc19ab973d9613fa
Reviewed-on: http://review.couchbase.org/34643
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>