[4.0] afec111 Fix vmod priv doc typo.

[Lasse Karstensen]

commit afec1119f8fe1f3ac9bbc00e98fbf3528463a103
Author: Dag Haavi Finstad <daghf at varnish-software.com>
Date:   Fri Jan 30 20:27:38 2015 +0100

    Fix vmod priv doc typo.
    
    Spotted by: gquintard

diff --git a/doc/sphinx/reference/vmod.rst b/doc/sphinx/reference/vmod.rst
index 5ad685f..c4d741b 100644
--- a/doc/sphinx/reference/vmod.rst
+++ b/doc/sphinx/reference/vmod.rst
@@ -273,7 +273,7 @@ malloc would look like this::
 	if (priv->priv == NULL) {
 		priv->priv = calloc(sizeof(struct myfoo), 1);
 		AN(priv->priv);
-		priv->priv = free;	/* free(3) */
+		priv->free = free;	/* free(3) */
 		mystate = priv->priv;
 		mystate->foo = 21;
 		...