Cleanup of LIBWRAP handling


Docs/manual.texi:
  Changelog
include/my_pthread.h:
  Fixed pthread_cond_timedwait() for HPUX and DCE threads
mysys/my_pthread.c:
  Fixed pthread_cond_timedwait() for HPUX and DCE threads
sql/item_func.cc:
  Fixed the GET_LOCK() works with HPUX and DCE threads
sql/mysqld.cc:
  Cleanup of LIBWRAP handling
sql/sql_parse.cc:
  Safety fix