Aria service threads are not "joined"

==11547== 608 bytes in 1 blocks are possibly lost in loss record 9 of 10

==11547==    at 0x4C2DCB5: calloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)

==11547==    by 0x4013504: allocate_dtv (dl-tls.c:322)

==11547==    by 0x4013504: _dl_allocate_tls (dl-tls.c:544)

==11547==    by 0x5C6E0D2: allocate_stack (allocatestack.c:588)

==11547==    by 0x5C6E0D2: pthread_create@@GLIBC_2.2.5 (pthread_create.c:537)

==11547==    by 0xA3FBAF: spawn_thread_v1 (pfs.cc:1910)

==11547==    by 0xA95761: inline_mysql_thread_create (mysql_thread.h:1255)

==11547==    by 0xA95FCB: ma_checkpoint_init (ma_checkpoint.c:337)

==11547==    by 0xA6C332: ha_maria_init(void*) (ha_maria.cc:3606)

==11547==    by 0x85F7A6: ha_initialize_handlerton(st_plugin_int*) (handler.cc:501)

==11547==    by 0x66A60C: plugin_initialize(st_mem_root*, st_plugin_int*, int*, char**, bool) (sql_plugin.cc:1379)

==11547==    by 0x66AEE4: plugin_init(int*, char**, int) (sql_plugin.cc:1601)

==11547==    by 0x58FA56: init_server_components() (mysqld.cc:4842)

==11547==    by 0x590B0B: mysqld_main(int, char**) (mysqld.cc:5437)

==11547==    by 0x586B75: main (main.cc:25)