Enable GridFTP detection by default. Track/log SSL client certs.

In the *service* field of connection records, GridFTP control channels
are labeled as "gridftp" and data channels as "gridftp-data".

Added *client_subject* and *client_issuer_subject* as &log'd fields to
SSL::Info record.  Also added *client_cert* and *client_cert_chain*
fields to track client cert chain.

testing/btest/scripts/base/protocols/ftp/gridftp.test

@@ -0,0 +1,21 @@
+# @TEST-EXEC: bro -r $TRACES/globus-url-copy.trace %INPUT
+# @TEST-EXEC: btest-diff notice.log
+# @TEST-EXEC: btest-diff conn.log
+# @TEST-EXEC: btest-diff ssl.log
+
+@load base/protocols/ftp/gridftp
+
+module GridFTP;
+
+redef size_threshold = 2;
+
+redef enum Notice::Type += {
+    Data_Channel
+};
+
+event GridFTP::data_channel_detected(c: connection)
+	{
+	local msg = fmt("GridFTP data channel over threshold %d bytes",
+	                size_threshold);
+	NOTICE([$note=Data_Channel, $msg=msg, $conn=c]);
+	}