storage_service: Fix default ring_delay time

It is 30 seconds instead of 5 seconds by default. To align with c*.

Pleas note, after this a node will takes at least 30 seconds to complete
a bootstrap.

service/storage_service.hh

@@ -163,7 +163,7 @@ private:
         }
         else
 #endif
-            return 5 * 1000;
+            return 30 * 1000;
     }
     /* This abstraction maintains the token/endpoint metadata information */
     token_metadata _token_metadata;