Fix checkstyle

Signed-off-by: Tran Ngoc Nhan <ngocnhan.tran1996@gmail.com>

Author: ngocnhan-tran1996

cas/src/main/java/org/springframework/security/cas/web/authentication/DefaultServiceAuthenticationDetails.java

@@ -110,7 +110,7 @@ public String toString() {
 	 */
 	private String getQueryString(final HttpServletRequest request, final Pattern artifactPattern) {
 		final String query = request.getQueryString();
-		String result = query == null ? "" : artifactPattern.matcher(query).replaceFirst("");
+		String result = (query != null) ? artifactPattern.matcher(query).replaceFirst("") : "";
 		if (result.isEmpty()) {
 			return null;
 		}