if no alg is explicitly set, use the default from the signer

Author: jricher

openid-connect-client/src/main/java/org/mitre/openid/connect/client/OIDCAuthenticationFilter.java

@@ -342,6 +342,10 @@ protected ClientHttpRequest createRequest(URI url, HttpMethod method) throws IOE
 
 // needs to be wired in to the bean
 signer = authenticationSignerService;
+
+if (alg == null) {
+alg = authenticationSignerService.getDefaultSigningAlgorithm();
+}
 }
 
 if (signer == null) {