Display 'created new cache in ' message only if output is terminal

cmd/restic/global.go

@@ -492,7 +492,7 @@ func OpenRepository(opts GlobalOptions) (*repository.Repository, error) {
 		return s, nil
 	}
 
-	if c.Created && !opts.JSON {
+	if c.Created && !opts.JSON && stdoutIsTerminal() {
 		Verbosef("created new cache in %v\n", c.Base)
 	}