mw/etcd: revert 'add fallthrough'

This removes 'fallthrough' for *etcd* which is not needed. This was
added in 00f5c7797 but is totally not needed and creates backwards
incompat behavior even.

Thanks to @johnbelamaric for pointing this out in #925.

middleware/etcd/etcd.go

@@ -21,16 +21,15 @@ import (
 
 // Etcd is a middleware talks to an etcd cluster.
 type Etcd struct {
-	Next        middleware.Handler
-	Fallthrough bool
-	Zones       []string
-	PathPrefix  string
-	Proxy       proxy.Proxy // Proxy for looking up names during the resolution process
-	Client      etcdc.KeysAPI
-	Ctx         context.Context
-	Inflight    *singleflight.Group
-	Stubmap     *map[string]proxy.Proxy // list of proxies for stub resolving.
-	Debugging   bool                    // Do we allow debug queries.
+	Next       middleware.Handler
+	Zones      []string
+	PathPrefix string
+	Proxy      proxy.Proxy // Proxy for looking up names during the resolution process
+	Client     etcdc.KeysAPI
+	Ctx        context.Context
+	Inflight   *singleflight.Group
+	Stubmap    *map[string]proxy.Proxy // list of proxies for stub resolving.
+	Debugging  bool                    // Do we allow debug queries.
 
 	endpoints []string // Stored here as well, to aid in testing.
 }