Polish SunJassKrb5LoginConfig !useTicketCache

The assertion of keyTabLocation should be independant of initializing the
keyTabLocation.

spring-security-kerberos-client/src/main/java/org/springframework/security/kerberos/client/config/SunJaasKrb5LoginConfig.java

@@ -74,8 +74,11 @@ public void afterPropertiesSet() throws Exception {
 			LOG.warn("Your keytab is in the classpath. This file needs special protection and shouldn't be in the classpath. JAAS may also not be able to load this file from classpath.");
 		}
 
-		if (!useTicketCache || keyTabLocation != null) {
+		if (!useTicketCache) {
 			Assert.notNull(keyTabLocation, "keyTabLocation must be specified when useTicketCache is false");
+		}
+
+		if (keyTabLocation != null) {
 			keyTabLocationAsString = keyTabLocation.getURL().toExternalForm();
 			if (keyTabLocationAsString.startsWith("file:")) {
 				keyTabLocationAsString = keyTabLocationAsString.substring(5);