Update DTLS error handling

DTLS now only outputs protocol violations once it saw something that
looked like a DTLS connection (at least a client hello). Before the
danger that it misinterprets something is too high.

It has a configurable number of invalid packets that it can skip over
(because other protocols might be interleaved with the connection) and a
maximum amount of Protocol violations that it outputs because of wrong
packet versions.

testing/btest/scripts/base/protocols/ssl/dtls-no-dtls.test

@@ -0,0 +1,15 @@
+# This tests checks that non-dtls connections to which we attach don't trigger tons of errors.
+
+# @TEST-EXEC: bro -C -r $TRACES/dns-txt-multiple.trace %INPUT
+# @TEST-EXEC: btest-diff .stdout
+
+event bro_init()
+	{
+	const add_ports = { 53/udp };
+	Analyzer::register_for_ports(Analyzer::ANALYZER_DTLS, add_ports);
+	}
+
+event protocol_violation(c: connection, atype: Analyzer::Tag, aid: count, reason: string)
+	{
+	print c$id, atype, reason;
+	}