Change SSLContext to use a ThreadLocalPRNG

Summary:Use a ThreadLocalPRNG insteaad of a per context RNG.  This avoids
calls to Random::seed on context creation which can get expensive
when many are created in an application.

Reviewed By: siyengar

Differential Revision: D3105501

fb-gh-sync-id: 92d987c27a1f190a98035ca25c23b994ca915007
fbshipit-source-id: 92d987c27a1f190a98035ca25c23b994ca915007

wangle/ssl/TLSTicketKeyManager.cpp

@@ -9,14 +9,14 @@
  */
 #include <wangle/ssl/TLSTicketKeyManager.h>
 
-#include <wangle/ssl/SSLStats.h>
-#include <wangle/ssl/SSLUtil.h>
-
+#include <folly/Random.h>
 #include <folly/String.h>
+#include <folly/io/async/AsyncTimeout.h>
 #include <openssl/aes.h>
 #include <openssl/rand.h>
 #include <openssl/ssl.h>
-#include <folly/io/async/AsyncTimeout.h>
+#include <wangle/ssl/SSLStats.h>
+#include <wangle/ssl/SSLUtil.h>
 
 #ifdef SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB
 using std::string;