wp-super-cache: don't write timestamp cache in config file

Fixes ai/issues#104

wp-content/plugins/wp-super-cache/wp-cache-phase2.php

@@ -3082,6 +3082,7 @@ function wp_cache_gc_watcher() {
 	}
 }
 
+
 if ( ! function_exists( 'apache_request_headers' ) ) {
 	/**
 	 * A fallback for get request headers.
@@ -3102,3 +3103,17 @@ if ( ! function_exists( 'apache_request_headers' ) ) {
 		return $headers;
 	}
 }
+
+/*
+ * Do not write the blog timestamp in the config file.
+ * wp-cache-config.php isn't writable by 'noblogs' user.
+ * https://git.autistici.org/ai/issues/issues/104
+
+function wpsc_timestamp_cache_update( $type, $permalink ) {
+	wp_cache_setting( 'wpsc_last_post_update', time() );
+}
+add_action( 'gc_cache', 'wpsc_timestamp_cache_update', 10, 2 );
+
+*/
+
+?>