Fix for LP#588251: doStartTableScan() result not checked.

The issue was that we didn't always check result of ha_rnd_init() which caused a problem for handlers that returned an error in this code.
- Changed prototype of ha_rnd_init() to ensure that we get a compile warning if result is not checked.
- Added ha_rnd_init_with_error() that prints error on failure.
- Checked all usage of ha_rnd_init() and ensure we generate an error message on failures.
- Changed init_read_record() to return 1 on failure.




sql/create_options.cc:
  Fixed wrong printf
sql/event_db_repository.cc:
  Check result from init_read_record()
sql/events.cc:
  Check result from init_read_record()
sql/filesort.cc:
  Check result from ha_rnd_init()
sql/ha_partition.cc:
  Check result from ha_rnd_init()
sql/ha_partition.h:
  Fixed compiler warning
sql/handler.cc:
  Added ha_rnd_init_with_error()
  Check result from ha_rnd_init()
sql/handler.h:
  Added ha_rnd_init_with_error()
  Changed prototype of ha_rnd_init() to ensure that we get a compile warning if result is not checked
sql/item_subselect.cc:
  Check result from ha_rnd_init()
sql/log.cc:
  Check result from ha_rnd_init()
sql/log_event.cc:
  Check result from ha_rnd_init()
sql/log_event_old.cc:
  Check result from ha_rnd_init()
sql/mysql_priv.h:
  init_read_record() now returns error code on failure
sql/opt_range.cc:
  Check result from ha_rnd_init()
sql/records.cc:
  init_read_record() now returns error code on failure
  Check result from ha_rnd_init()
sql/sql_acl.cc:
  Check result from init_read_record()
sql/sql_cursor.cc:
  Print error if ha_rnd_init() fails
sql/sql_delete.cc:
  Check result from init_read_record()
sql/sql_help.cc:
  Check result from init_read_record()
sql/sql_plugin.cc:
  Check result from init_read_record()
sql/sql_select.cc:
  Check result from ha_rnd_init()
  Print error if ha_rnd_init() fails.
sql/sql_servers.cc:
  Check result from init_read_record()
sql/sql_table.cc:
  Check result from init_read_record()
sql/sql_udf.cc:
  Check result from init_read_record()
sql/sql_update.cc:
  Check result from init_read_record()
storage/example/ha_example.cc:
  Don't return error on rnd_init()
storage/ibmdb2i/ha_ibmdb2i.cc:
  Removed not relevant comment

storage/example/ha_example.cc

@@ -588,7 +588,7 @@ int ha_example::index_last(uchar *buf)
 int ha_example::rnd_init(bool scan)
 {
   DBUG_ENTER("ha_example::rnd_init");
-  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+  DBUG_RETURN(0);
 }
 
 int ha_example::rnd_end()