memcached: revert earlier doc change regarding minimum library version (we now have backward compatibility built in)

modules/memcached/README

@@ -169,7 +169,7 @@ xlog("stored value is $mct(test)"); # will return <null>
 
    The following libraries or applications must be installed before
    running Kamailio with this module loaded:
-     * the libmemcached library (version 0.38 or higher).
+     * the libmemcached library.
      * the memcached server implementation.
 
 4. Parameters

modules/memcached/doc/memcached_admin.xml

@@ -132,7 +132,7 @@ xlog("stored value is $mct(test)"); # will return <null>
 			<itemizedlist>
 			<listitem>
 			<para>
-				<emphasis>the <ulink url="http://libmemcached.org/">libmemcached</ulink> library (version 0.38 or higher)</emphasis>.
+				<emphasis>the <ulink url="http://libmemcached.org/">libmemcached</ulink> library</emphasis>.
 			</para>
 			</listitem>
 			<listitem>