modules/auth: fixed path in auth.xml

src/modules/auth/auth.xml

@@ -3,7 +3,7 @@
 	"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
 
 <!-- Include general documentation entities -->
-<!ENTITY % docentities SYSTEM "../../../../doc/docbook/entities.xml">
+<!ENTITY % docentities SYSTEM "../../../doc/docbook/entities.xml">
 %docentities;
 
 ]>