Merge remote-tracking branch 'origin/topic/awelzel/more-dns-stats'

* origin/topic/awelzel/more-dns-stats:
  get_dns_stats: Expose total cache size and cached text entries

testing/btest/Baseline/bifs.get_dns_stats/out

@@ -0,0 +1,2 @@
+### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
+[requests=0, successful=0, failed=0, pending=0, cached_hosts=0, cached_addresses=0, cached_texts=0, cached_total=0]

testing/btest/bifs/get_dns_stats.test

@@ -0,0 +1,8 @@
+# @TEST-DOC: With FAKE_DNS mode caching is disabled, so testing is difficult, invoke the bif once at least.
+# @TEST-EXEC: zeek -b %INPUT >out
+# @TEST-EXEC: btest-diff out
+
+event zeek_init()
+	{
+	print get_dns_stats();
+	}