Item_func_from_days::get_date didn't change 'hr', 'min' and some
other fields of incoming ltime, so they got random values.

bzeroing of the ltime added


mysql-test/r/func_time.result:
  appropriate test result
mysql-test/t/func_time.test:
  test case
sql/item_timefunc.cc:
  cleaning ltime added