Don't make OLD_PASSWORD() a reserved word


mysql-test/r/explain.result:
  Test select count(*)
mysql-test/r/func_crypt.result:
  Test old_password()
mysql-test/t/explain.test:
  Test select count(*)
mysql-test/t/func_crypt.test:
  Test old_password()
sql/item_create.cc:
  Don't make OLD_PASSWORD() a reserved word
sql/item_create.h:
  Don't make OLD_PASSWORD() a reserved word
sql/lex.h:
  Don't make OLD_PASSWORD() a reserved word
sql/opt_range.cc:
  Remove blank space
sql/opt_sum.cc:
  Fix problem in MIN/MAX optimisation