allow handler::info to return an error code (that will be returned to the user)


sql/ha_berkeley.cc:
  update handler::info interface to return int
sql/ha_berkeley.h:
  update handler::info interface to return int
sql/ha_heap.cc:
  update handler::info interface to return int
sql/ha_heap.h:
  update handler::info interface to return int
sql/ha_innodb.cc:
  update handler::info interface to return int
sql/ha_innodb.h:
  update handler::info interface to return int
sql/ha_myisam.cc:
  update handler::info interface to return int
sql/examples/ha_archive.cc:
  update handler::info interface to return int
sql/examples/ha_archive.h:
  update handler::info interface to return int
sql/examples/ha_example.cc:
  update handler::info interface to return int
sql/examples/ha_example.h:
  update handler::info interface to return int
sql/examples/ha_tina.cc:
  update handler::info interface to return int
sql/examples/ha_tina.h:
  update handler::info interface to return int
sql/ha_myisam.h:
  update handler::info interface to return int
sql/ha_myisammrg.cc:
  update handler::info interface to return int
sql/ha_myisammrg.h:
  update handler::info interface to return int
sql/ha_ndbcluster.cc:
  update handler::info interface to return int
sql/ha_ndbcluster.h:
  update handler::info interface to return int
sql/handler.h:
  update handler::info interface to return int
sql/opt_sum.cc:
  If we get an error when using handler::info to get count(*),
  print and return the error.
sql/sql_select.cc:
  if error, set fatal error.