bugfix - cache primaries declaration of support for up to 6 hours, not six minutes

lib/browserid/primary.js

@@ -47,7 +47,7 @@ jwk = require('jwcrypto/jwk');
 const WELL_KNOWN_URL = "/.well-known/vep";
 
 // cache .well-known/vep for six hours
-const MAX_CACHE_MS = (6 * 60 * 1000);
+const MAX_CACHE_MS = (6 * 60 * 60 * 1000);
 
 function parseWellKnownBody(body, domain) {
   var v = JSON.parse(body);