[4.1] 4edc05c trivial comment fix

[Lasse Karstensen]

commit 4edc05cc2a96338ef95de6e25c3eaff1005d50e5
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Mon Apr 25 16:24:36 2016 +0200

    trivial comment fix

diff --git a/bin/varnishd/cache/cache_ban_build.c b/bin/varnishd/cache/cache_ban_build.c
index b3bda03..6fcbab8 100644
--- a/bin/varnishd/cache/cache_ban_build.c
+++ b/bin/varnishd/cache/cache_ban_build.c
@@ -48,7 +48,7 @@ struct ban_proto {
 };
 
 /*--------------------------------------------------------------------
- * Variables we can purge on
+ * Variables we can ban on
  */
 
 static const struct pvar {