Update anonymize_headers.pcre

data/conf/postfix/anonymize_headers.pcre

@@ -1,4 +1,4 @@
-#if /^\s*Received:.*Authenticated sender.*\(Postcow\)/
+if /^\s*Received:.*Authenticated sender.*\(Postcow\)/
 /^\s*Received:.*Authenticated sender:(.+)/
   REPLACE Received: from localhost (localhost [127.0.0.1]) (Authenticated sender:$1
 endif