"Valgrind leak in closecon_handlerton"
  plugin_shutdown() calls plugin_deinitialize() which calls ha_finalize_handlerton().
  ndbcluster_end() fails to wait for the ndb utility thread to exit which results in
  the handlerton struct being freed before the ndb utility thread has destroyed it's THD
  but before the plugin has been marked as UNINITIALIZED

Bug is caused by misuse of abort_loops variable and not locking mutex during calls to
pthread condition variable functions causing a race in valgrind's pthread_cond_wait
implementation.