Fix build break on SmartOS

error: call of overloaded 'log(int)' is ambiguous

Change-Id: I58af2a6e7ae3a171cc4f5c8a4d301585af86cc3e
Reviewed-on: http://review.couchbase.org/42717
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Chiyoung Seo <chiyoung@couchbase.com>