tokudb: fixup PFS key double-free during shutdown

TokuDB will be crashed during shutdown due to PFS key double-free.

(gdb) bt
#0  __pthread_kill (threadid=<optimized out>, signo=signo@entry=11) at ../sysdeps/unix/sysv/linux/pthread_kill.c:62
#1  0x0000000000f6b3e7 in my_write_core (sig=sig@entry=11) at /u01/tokudb/mysys/stacktrace.c:249
#2  0x000000000086b6e5 in handle_fatal_signal (sig=11) at /u01/tokudb/sql/signal_handler.cc:223
#3  <signal handler called>
#4  destroy_mutex (pfs=0x7f8fb71c9900) at /u01/tokudb/storage/perfschema/pfs_instr.cc:327
#5  0x00000000013c574a in pfs_destroy_mutex_v1 (mutex=<optimized out>) at /u01/tokudb/storage/perfschema/pfs.cc:1833
#6  0x0000000000fc350a in inline_mysql_mutex_destroy (that=0x1f84ea0 <tokudb_map_mutex>) at /u01/tokudb/include/mysql/psi/mysql_thread.h:681
#7  tokudb::thread::mutex_t::~mutex_t (this=0x1f84ea0 <tokudb_map_mutex>, __in_chrg=<optimized out>) at /u01/tokudb/storage/tokudb/tokudb_thread.h:214
#8  0x00007f8fbb38cff8 in _run_exit_handlers (status=status@entry=0, listp=0x7f8fbb7175f8 <_exit_funcs>, run_list_atexit=run_list_atexit@entry=true) at exit.c:82
#9  0x00007f8fbb38d045 in __GI_exit (status=status@entry=0) at exit.c:104
#10 0x000000000085b7b5 in mysqld_exit (exit_code=exit_code@entry=0) at /u01/tokudb/sql/mysqld.cc:1205
#11 0x0000000000865fa6 in mysqld_main (argc=46, argv=0x7f8fbaeb3088) at /u01/tokudb/sql/mysqld.cc:5430
#12 0x00007f8fbb373830 in __libc_start_main (main=0x78d700 <main(int, char**)>, argc=10, argv=0x7ffd36ab1a28, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffd36ab1a18) at ../csu/libc-start.c:291
#13 0x00000000007a7b79 in _start ()

And the AddressSanitizer errors:
==27219==ERROR: AddressSanitizer: heap-use-after-free on address 0x7f009b12d118 at pc 0x00000265d80b bp 0x7ffd3bb7ffb0 sp 0x7ffd3bb7ffa0
READ of size 8 at 0x7f009b12d118 thread T0
#0 0x265d80a in destroy_mutex(PFS_mutex*) /u01/tokudb/storage/perfschema/pfs_instr.cc:323
#1 0x1cfaef3 in inline_mysql_mutex_destroy /u01/tokudb/include/mysql/psi/mysql_thread.h:681
#2 0x1cfaef3 in tokudb::thread::mutex_t::~mutex_t() /u01/tokudb/storage/tokudb/tokudb_thread.h:214
#3 0x7f009d512ff7 (/lib/x86_64-linux-gnu/libc.so.6+0x39ff7)
#4 0x7f009d513044 in exit (/lib/x86_64-linux-gnu/libc.so.6+0x3a044)
#5 0x9a8239 in mysqld_exit /u01/tokudb/sql/mysqld.cc:1205
#6 0x9b210f in unireg_abort /u01/tokudb/sql/mysqld.cc:1175
#7 0x9b629e in init_server_components /u01/tokudb/sql/mysqld.cc:4509
#8 0x9b8aca in mysqld_main(int, char**) /u01/tokudb/sql/mysqld.cc:5001
#9 0x7f009d4f982f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
#10 0x7e8308 in _start (/home/ubuntu/mysql_20161216/bin/mysqld+0x7e8308)

storage/tokudb/hatoku_hton.cc

@@ -310,7 +310,6 @@ static int tokudb_init_func(void *p) {
     count = array_elements(all_tokudb_rwlocks);
     mysql_rwlock_register("tokudb", all_tokudb_rwlocks, count);
 
-    tokudb_map_mutex.reinit(tokudb_map_mutex_key);
 #endif /* HAVE_PSI_INTERFACE */
 
     db_env = NULL;