Fix up documentation for ESI syntax

The syntax for enabling ESI has changed in trunk, update the
documentation to match.

doc/sphinx/tutorial/advanced_topics.rst

@@ -54,10 +54,10 @@ your hit rate and reduce the load on your servers. ESI looks like this::
   </BODY>
   </HTML>
 
-ESI is processed in vcl_fetch by using the *esi* keyword.::
+ESI is processed in vcl_fetch by setting *do_esi* to true.::
 
   sub vcl_fetch {
       if (req.url == "/test.html") {
-	  esi;  /* Do ESI processing */
+	  set beresp.do_esi = true;  /* Do ESI processing */
       }
   }

doc/sphinx/tutorial/esi.rst

@@ -47,7 +47,7 @@ For ESI to work you need to activate ESI processing in VCL, like this:::
 
     sub vcl_fetch {
     	if (req.url == "/test.html") {
-           esi;        		     /* Do ESI processing		*/
+           set beresp.do_esi = true; /* Do ESI processing		*/
            set obj.ttl = 24 h; 	     /* Sets the TTL on the HTML above  */
     	} elseif (req.url == "/cgi-bin/date.cgi") {
            set obj.ttl = 1m;         /* Sets a one minute TTL on	*/

doc/sphinx/tutorial/vcl.rst

@@ -77,9 +77,6 @@ The most common actions to call are these:
 *deliver*
  Deliver the cached object to the client.  Usually called in vcl_fetch. 
 
-*esi*
- ESI-process the fetched document.
-
 Requests, responses and objects
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~