eth/*: golint updates for this or self warning, pr updated per feedback

eth/backend.go

@@ -325,7 +325,7 @@ func (s *Ethereum) Etherbase() (eb common.Address, err error) {
 	return common.Address{}, fmt.Errorf("etherbase must be explicitly specified")
 }
 
-// SetEtherbase in js console via admin interface or wrapper from cli flags
+// SetEtherbase sets the mining reward address.
 func (s *Ethereum) SetEtherbase(etherbase common.Address) {
 	s.lock.Lock()
 	s.etherbase = etherbase

eth/handler.go

@@ -769,4 +769,4 @@ func (pm *ProtocolManager) NodeInfo() *NodeInfo {
 		Config:     pm.blockchain.Config(),
 		Head:       currentBlock.Hash(),
 	}
-}
+}