Bug#818708: didiwiki regression: fix for CVE-2013-7448 renders many existing pages inaccessible

[Ignace Mouzannar]

Thanks Sergio for your review and input. Here is the patch I will be uploading.

----
+    if (page_name[0] == '/')
+        return FALSE;
+
+    if (strncmp(page_name, "../", 3) == 0)
+        return FALSE;
+
+    if (strstr(page_name, "/../"))
+        return FALSE;
----

Cheers,
 Ignace M