MDEV-4594 - CREATE SERVER crashes embedded

mysql-test/r/servers.result:
  Added test case for MDEV-4594.
mysql-test/t/servers.test:
  Added test case for MDEV-4594.
sql/mysqld.cc:
  Move servers_init() call to init_server_components(), so it is called
  for embedded as well.
  
  Call servers_free() even if NO_EMBEDDED_ACCESS_CHECKS defined (because
  we call servers_init() anyway).

mysql-test/r/servers.result

+#
+# MDEV-4594 - CREATE SERVER crashes embedded
+#
+CREATE SERVER s1 FOREIGN DATA WRAPPER mysql OPTIONS(HOST 'localhost');
+SELECT * FROM mysql.servers;
+Server_name	Host	Db	Username	Password	Port	Socket	Wrapper	Owner
+s1	localhost				0		mysql	
+DROP SERVER s1;

mysql-test/t/servers.test

+# Generic tests for servers (do not require FEDERATED)
+
+--echo #
+--echo # MDEV-4594 - CREATE SERVER crashes embedded
+--echo #
+CREATE SERVER s1 FOREIGN DATA WRAPPER mysql OPTIONS(HOST 'localhost');
+SELECT * FROM mysql.servers;
+DROP SERVER s1;

sql/mysqld.cc

@@ -1847,8 +1847,8 @@ void clean_up(bool print_message)
   my_tz_free();
   my_dboptions_cache_free();
   ignore_db_dirs_free();
-#ifndef NO_EMBEDDED_ACCESS_CHECKS
   servers_free(1);
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
   acl_free(1);
   grant_free();
 #endif
@@ -4668,6 +4668,8 @@ a file name for --log-bin-index option", opt_binlog_index_name);
   init_update_queries();
   init_global_user_stats();
   init_global_client_stats();
+  if (!opt_bootstrap)
+    servers_init(0);
   DBUG_RETURN(0);
 }
 
@@ -5074,9 +5076,6 @@ int mysqld_main(int argc, char **argv)
   if (!opt_noacl)
     (void) grant_init();
 
-  if (!opt_bootstrap)
-    servers_init(0);
-
   if (!opt_noacl)
   {
 #ifdef HAVE_DLOPEN