Ensure Async is deinited properly

The global thread local keys were not being deinited properly in async.

Reviewed-by: Rich Salz <rsalz@openssl.org>
diff --git a/crypto/init.c b/crypto/init.c
index cbe07df..613606e 100644
--- a/crypto/init.c
+++ b/crypto/init.c
@@ -580,6 +580,16 @@
         COMP_zlib_cleanup();
     }
 
+#ifndef OPENSSL_NO_ASYNC
+    if (async_inited) {
+# ifdef OPENSSL_INIT_DEBUG
+        fprintf(stderr, "OPENSSL_INIT: OPENSSL_cleanup: "
+                        "async_deinit()\n");
+# endif
+        async_deinit();
+    }
+#endif
+
 #ifndef OPENSSL_NO_ENGINE
     if (engine_inited) {
 # ifdef OPENSSL_INIT_DEBUG