lnd+macaroons: specify location when creating macaroon service

To allow the macaroon service to be used in other projects, we want the
location to be passed in as a parameter instead of being hard coded.

macaroons/service.go

@@ -54,7 +54,7 @@ type Service struct {
 // listing the same checker more than once is not harmful. Default checkers,
 // such as those for `allow`, `time-before`, `declared`, and `error` caveats
 // are registered automatically and don't need to be added.
-func NewService(dir string, checks ...Checker) (*Service, error) {
+func NewService(dir, location string, checks ...Checker) (*Service, error) {
 	// Ensure that the path to the directory exists.
 	if _, err := os.Stat(dir); os.IsNotExist(err) {
 		if err := os.MkdirAll(dir, 0700); err != nil {
@@ -77,7 +77,7 @@ func NewService(dir string, checks ...Checker) (*Service, error) {
 	}
 
 	macaroonParams := bakery.BakeryParams{
-		Location:     "lnd",
+		Location:     location,
 		RootKeyStore: rootKeyStore,
 		// No third-party caveat support for now.
 		// TODO(aakselrod): Add third-party caveat support.