Added exception for logged in users

Exception rule to not serve cached pages if the user has a cookie value indicating that they are logged in.

wp-ffpc-nginx-sample.conf

@@ -127,7 +127,10 @@ MEMCACHED_SERVERS
 						set $memcached_request 0;
 				}
 
-				LOGGEDIN_EXCEPTION
+				# don't serve cached pages if user is logged in
+				if ($http_cookie ~* "wordpress_logged_in_" ) {
+					set $memcached_request 0;
+				}
 
 				if ( $memcached_request = 1) {
 						memcached_pass memcached-servers;