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

sql/sql_help.cc

@@ -182,11 +182,14 @@ int search_topics(THD *thd, TABLE *topics, struct st_find_field *find_fields,
 		  SQL_SELECT *select, List<String> *names,
 		  String *name, String *description, String *example)
 {
-  DBUG_ENTER("search_topics");
   int count= 0;
-
   READ_RECORD read_record_info;
-  init_read_record(&read_record_info, thd, topics, select, 1, 0, FALSE);
+  DBUG_ENTER("search_topics");
+
+  /* Should never happen. As this is part of help, we can ignore this */
+  if (init_read_record(&read_record_info, thd, topics, select, 1, 0, FALSE))
+    DBUG_RETURN(0);
+
   while (!read_record_info.read_record(&read_record_info))
   {
     if (!select->cond->val_int())		// Doesn't match like
@@ -222,11 +225,13 @@ int search_topics(THD *thd, TABLE *topics, struct st_find_field *find_fields,
 int search_keyword(THD *thd, TABLE *keywords, struct st_find_field *find_fields,
                    SQL_SELECT *select, int *key_id)
 {
-  DBUG_ENTER("search_keyword");
   int count= 0;
-
   READ_RECORD read_record_info;
-  init_read_record(&read_record_info, thd, keywords, select, 1, 0, FALSE);
+  DBUG_ENTER("search_keyword");
+  /* Should never happen. As this is part of help, we can ignore this */
+  if (init_read_record(&read_record_info, thd, keywords, select, 1, 0, FALSE))
+    DBUG_RETURN(0);
+
   while (!read_record_info.read_record(&read_record_info) && count<2)
   {
     if (!select->cond->val_int())		// Dosn't match like
@@ -347,10 +352,11 @@ int search_categories(THD *thd, TABLE *categories,
   Field *pcat_id= find_fields[help_category_help_category_id].field;
   int count= 0;
   READ_RECORD read_record_info;
-
   DBUG_ENTER("search_categories");
 
-  init_read_record(&read_record_info, thd, categories, select,1,0,FALSE);
+  /* Should never happen. As this is part of help, we can ignore this */
+  if (init_read_record(&read_record_info, thd, categories, select,1,0,FALSE))
+    DBUG_RETURN(0);
   while (!read_record_info.read_record(&read_record_info))
   {
     if (select && !select->cond->val_int())
@@ -381,10 +387,13 @@ int search_categories(THD *thd, TABLE *categories,
 void get_all_items_for_category(THD *thd, TABLE *items, Field *pfname,
 				SQL_SELECT *select, List<String> *res)
 {
+  READ_RECORD read_record_info;
   DBUG_ENTER("get_all_items_for_category");
 
-  READ_RECORD read_record_info;
-  init_read_record(&read_record_info, thd, items, select,1,0,FALSE);
+  /* Should never happen. As this is part of help, we can ignore this */
+  if (init_read_record(&read_record_info, thd, items, select,1,0,FALSE))
+    DBUG_VOID_RETURN;
+
   while (!read_record_info.read_record(&read_record_info))
   {
     if (!select->cond->val_int())