SET @@global.log_output

Deadlock chain:
rdlock(LOCK_logger) -> lock(LOCK_open)     SELECT 1
lock(LOCK_open)     -> lock(LOCK_status)   DROP TABLE t1
lock(LOCK_status)   -> lock(LOCK_g_s_v)    SHOW STATUS
lock(LOCK_g_s_)     -> wrlock(LOCK_logger) SET @@global.log_output=DEFAULT

Fixed by removing relationship between LOCK_status and
LOCK_global_system_variables during SHOW STATUS: we don't really need
LOCK_global_system_variables when accessing status vars.