spicy-redis: Abort parsing if server data comes first

Redis seems to only want client data first to request server data. The
DPD signature seems to pick up on some cases where server data comes
first, but is otherwise "valid" RESP. See if this helps lower FP rates.

testing/btest/scripts/base/protocols/redis/start-with-server.zeek

@@ -0,0 +1,14 @@
+# @TEST-DOC: Test that Redis does not parse if it starts with the server data
+#
+# @TEST-EXEC: zeek -Cr $TRACES/redis/start-with-server.pcap base/protocols/redis %INPUT >output
+# @TEST-EXEC: btest-diff output
+
+event Redis::command(c: connection, is_orig: bool, command: Redis::Command)
+	{
+	print "BAD", command;
+	}
+
+event Redis::server_data(c: connection, is_orig: bool, dat: Redis::ServerData)
+	{
+	print "BAD", dat;
+	}