Add tests for DNSSEC sign statistics

This adds tests to the statschannel system test for testing if
the dnskey sign operation counters are incremented correctly.

It tests three cases:

1. A zone maintenance event where all the signatures that are about
   to expire are resigned.
2. A dynamic update event where the new RR and other relevant records
   (SOA, NSEC) are resigned.
3. Adding a standby key, that means the DNSKEY and SOA RRset are
   resigned.

bin/tests/system/statschannel/zones-xml.pl

@@ -0,0 +1,38 @@
+#!/usr/bin/perl
+#
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+# zones-xml.pl:
+# Parses the XML version of the dnssec sign stats for the
+# "dnssec" zone in the default view into a normalized format.
+
+use XML::Simple;
+
+my $file = $ARGV[0];
+
+my $ref = XMLin($file);
+
+my $counters = $ref->{views}->{view}->{_default}->{zones}->{zone}->{dnssec}->{counters};
+
+foreach $group (@$counters) {
+
+    my $type = $group->{type};
+
+    if ($type eq "dnssec") {
+        my $prefix = "dnskey sign operations ";
+        if (exists $group->{counter}->{name}) {
+            print $prefix . $group->{counter}->{name} . ": " . $group->{counter}->{content} . "\n";
+	} else {
+            foreach $key (keys %{$group->{counter}}) {
+                print $prefix . $key . ": ". $group->{counter}->{$key}->{content} ."\n";
+            }
+        }
+    }
+}