MDL-9742 - changed tabs to spaces in a few places where there are one

or two

auth/shibboleth/README.txt

@@ -162,7 +162,7 @@ Example file:
         $result["country"] = $country;
         $result["department"] = $institution;
         $result["description"] = "I am a Shibboleth user";
-	
+
     }
 
 ?>

auth/shibboleth/auth.php

@@ -148,9 +148,9 @@ class auth_plugin_shibboleth extends auth_plugin_base {
 
     function loginpage_hook() {
         global $SESSION, $CFG;
-	
-	// Prevent username from being shown on login page after logout
-	$CFG->nolastloggedin = true;
+
+        // Prevent username from being shown on login page after logout
+        $CFG->nolastloggedin = true;
 
         return;
     }

auth/shibboleth/index.php

@@ -44,7 +44,7 @@
             
             // Don't show username on login page
             set_moodle_cookie('nobody');
-	    
+
             set_login_session_preferences();
             
             unset($SESSION->lang);