fixed inadvertent consistency bug in granting offline_access to clients

openid-connect-server/src/main/java/org/mitre/openid/connect/web/ClientDynamicRegistrationEndpoint.java

@@ -91,7 +91,11 @@ public class ClientDynamicRegistrationEndpoint {
 
 			// set default grant types if needed
 			if (newClient.getGrantTypes() == null || newClient.getGrantTypes().isEmpty()) { 
-				newClient.setGrantTypes(Sets.newHashSet("authorization_code")); // allow authorization code grant type by default
+				if (newClient.getScope().contains("offline_access")) { // client asked for offline access
+					newClient.setGrantTypes(Sets.newHashSet("authorization_code", "refresh_token")); // allow authorization code and refresh token grant types by default
+				} else {
+					newClient.setGrantTypes(Sets.newHashSet("authorization_code")); // allow authorization code grant type by default
+				}
 			}
 			
 			// set default response types if needed