simplify assertNull

Author: jetersen

src/test/java/com/bettercloud/vault/api/pki/RoleOptionsTests.java

@@ -12,7 +12,7 @@ public void RoleOptionsTests() {
         RoleOptions roleOptions = new RoleOptions();
         Assert.assertNotNull(roleOptions);
 
-        Assert.assertEquals(roleOptions.getAllowedDomains(), null);
+        Assert.assertNull(roleOptions.getAllowedDomains());
 
         roleOptions.allowAnyName(true);
         roleOptions.allowBareDomains(true);