clean up golint messages on Exported methods within bucket.go
clean up golint messages on Exported methods within bucket.go

* add comments per golang conventions so the Exported methods appear in Godoc

Change-Id: I26a33195d43728386ac36dbf202ebf887d191e76
Reviewed-on: http://review.couchbase.org/63855
Reviewed-by: Brett Lawson <c8c4369773d7d7226e031f0c4af62e3f38a08510@gmail.com>
Tested-by: Brett Lawson <c8c4369773d7d7226e031f0c4af62e3f38a08510@gmail.com>

brett19/gocb