stun: updated docs to reflect that it no longer depends on external libs

(cherry picked from commit 305e7b5693e71d2027f8e6462129f8c9f01ad76d)

modules/stun/doc/stun_admin.xml

@@ -41,7 +41,7 @@
 		&kamailio; with this module loaded:
 		<itemizedlist>
 		<listitem>
-		<para><emphasis>OpenSSL</emphasis>.</para>
+		<para><emphasis>none</emphasis>.</para>
 		</listitem>
 		</itemizedlist>
 		</para>