Removed double my_thread_end() which caused fatal error on windows if mysqld died on startup


myisam/mi_extra.c:
  Fixed bug in ALTER TABLE ... DISABLE/ENABLE KEYS
mysql-test/r/alter_table.result:
  Fixed bug in ALTER TABLE ... DISABLE/ENABLE KEYS
mysql-test/t/alter_table.test:
  Test DISABLE/ENABLE KEY
sql/ha_myisam.cc:
  Fixed bug in ALTER TABLE ... DISABLE/ENABLE KEYS
sql/mysqld.cc:
  Removed double my_thread_end() which caused fatal error on windows if mysqld died on startup
sql/sql_table.cc:
  Fixed bug in ALTER TABLE ... DISABLE/ENABLE KEYS
sql/table.cc:
  Fixed bug in ALTER TABLE ... DISABLE/ENABLE KEYS
sql/table.h:
  Fixed bug in ALTER TABLE ... DISABLE/ENABLE KEYS