Fix missing backspace

lib/_autoload_modules.php

@@ -104,8 +104,8 @@ function sspmodAutoloadPSR0($className)
     if (!class_exists($className, false) && !interface_exists($className, false)) {
         // the file exists, but the class is not defined. Is it using namespaces?
         $nspath = join('\\', $path);
-        if (class_exists('SimpleSAML\Module\\'.$module.'\\'.$nspath) ||
-            interface_exists('SimpleSAML\Module\\'.$module.'\\'.$nspath)
+        if (class_exists('SimpleSAML\\Module\\'.$module.'\\'.$nspath) ||
+            interface_exists('SimpleSAML\\Module\\'.$module.'\\'.$nspath)
         ) {
             // the class has been migrated, create an alias and warn about it
             \SimpleSAML\Logger::warning(