增加ssl_service_cache模块，用以记录历史的证书和pinning状态。

platform/src/ssl_service_cache.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <tfe_types.h>
+#include <ssl_utils.h>
+#include <event2/event.h>
+
+#define PINNING_ST_NOT_PINNING		0
+#define PINNING_ST_PINNING			1
+#define PINNING_ST_MAYBE_PINNING	2
+struct ssl_service_desc
+{
+	char pinning_status;
+	char is_ev;
+	char is_ct;
+};
+
+struct ssl_service_cache;
+struct ssl_service_cache* ssl_service_cache_init();
+
+int ssl_service_cache_read(struct ssl_chello* chello,  struct ssl_service_desc* result);
+int ssl_service_cache_log_fail(struct ssl_chello* chello);
+