KEYCLOAK-3147 Don't allow authRequest without redirect_uri parameter

 src/main/java/org/keycloak/protocol/cas/utils/RedirectUtils.java

@@ -69,13 +69,8 @@

    private static String verifyRedirectUri(UriInfo uriInfo, String rootUrl, String redirectUri, RealmModel realm, Set<String> validRedirects) {
        if (redirectUri == null) {
            if (validRedirects.size() != 1) return null;
            String validRedirect = validRedirects.iterator().next();
            int idx = validRedirect.indexOf("/*");
            if (idx > -1) {
                validRedirect = validRedirect.substring(0, idx);
            }
            redirectUri = validRedirect;
            logger.debug("No Redirect URI parameter specified");
            return null;
        } else if (validRedirects.isEmpty()) {
            logger.debug("No Redirect URIs supplied");
            redirectUri = null;