fix backend sanity failure (take 2)

backend.php

@@ -748,7 +748,9 @@
 		}
 
 		if ($subop == "sanityCheck") {
-			sanity_check($link);
+			if (sanity_check($link)) {
+				print "<error error-code=\"0\"/>";
+			}
 		}
 
 		if ($subop == "globalPurge") {

tt-rss.js

@@ -111,6 +111,8 @@ function backend_sanity_check_callback() {
 	if (xmlhttp.readyState == 4) {
 
 		try {
+
+			alert(xmlhttp.responseText);
 		
 			if (!xmlhttp.responseXML) {
 				fatalError(3);