MDL-20901 fixed input validation

mod/survey/save.php

@@ -6,7 +6,7 @@
 
 // Make sure this is a legitimate posting
 
-    if (!$formdata = data_submitted("$CFG->wwwroot/mod/survey/view.php")) {
+    if (!$formdata = data_submitted("$CFG->wwwroot/mod/survey/view.php") or !confirm_sesskey()) {
         error("You are not supposed to use this script like that.");
     }
 

mod/survey/view.php

@@ -111,6 +111,7 @@
     echo "<form method=\"post\" action=\"save.php\" id=\"surveyform\">";
     echo '<div>';
     echo "<input type=\"hidden\" name=\"id\" value=\"$id\" />";
+    echo "<input type=\"hidden\" name=\"sesskey\" value=\"".sesskey()."\" />";
 
     print_simple_box(format_text($survey->intro), 'center', '70%', '', 5, 'generalbox', 'intro');