WatchNames: return errors via WebSocket
The previous wrangler commit included all of the v2 changes. Except for the import paths changes.
Signed-off-by: Silvio Moioli <silvio@moioli.net>
ByNames could previously return a nil value and a nil error. This caused issues when other parts of the application (pkg/stores/partition/parallel.go) tried to use the result. Now this will return an empty list on the error condition, instead of nil
