multi: remove dead code

watchtower/wtclient/session_queue.go

@@ -15,10 +15,6 @@ import (
 	"github.com/lightningnetwork/lnd/watchtower/wtwire"
 )
 
-// retryInterval is the default duration we will wait between attempting to
-// connect back out to a tower if the prior state update failed.
-const retryInterval = 2 * time.Second
-
 // reserveStatus is an enum that signals how full a particular session is.
 type reserveStatus uint8