- Always make rnd_pos reposition the cursor in the fetched result set.


mysql-test/r/federated.result:
  Update test result
mysql-test/t/federated.test:
  Add test for bug#17377
sql/ha_federated.cc:
  Remove the "scan_flag" variable. rnd_pos should always move to a new position in the result set. 
  The "scan" flag in rnd_init will protect from the old result set being 
  closed and a new fecthed. I think the "scan_flag" was added before check of the "scan" argument in rnd_init was added.
sql/ha_federated.h:
  Remove class variable "scan_flag"