The problem was that THD::row_count_func was zeroed too. It was zeroed
as a fix for bug 4905 "Stored procedure doesn't clear for "Rows affected"
However, the proper solution is not to zero, because THD::row_count_func has
been set to -1 already in mysql_execute_command(), a later fix, which obsoletes
the incorrect fix of #4095


mysql-test/r/sp.result:
  update result
mysql-test/t/sp.test:
  test for bug#23760 ROW_COUNT() and store procedure not owrking together
sql/sql_parse.cc:
  Remove zeroing for thd->row_count_func
  The fix for #4905 wasn't right. Now, it's ok without this zeroing
  because if there was an error THD::