Remove some redundant or unused code from InnoDB (feedback from

Marko after applying latest snapshot).

storage/innobase/handler/ha_innodb.cc

@@ -947,8 +947,6 @@ check_trx_exists(
 		/* Update the info whether we should skip XA steps that eat
 		CPU time */
 		trx->support_xa = THDVAR(thd, support_xa);
-
-		thd_to_trx(thd) = trx;
 	} else {
 		if (trx->magic_n != TRX_MAGIC_N) {
 			mem_analyze_corruption(trx);

storage/innobase/include/trx0trx.h

@@ -512,14 +512,6 @@ struct trx_struct{
 	ulint		mysql_process_no;/* since in Linux, 'top' reports
 					process id's and not thread id's, we
 					store the process number too */
-	ibool		allow_duplicates;/* normally FALSE, but if the user
-					wants to update duplicate rows,
-					(in table inserts, for example) we
-					set this TRUE */
-	ibool		replace_duplicates;/* normally FALSE, but if the user
-					wants to replace duplicate rows,
-					(in table inserts, for example) we
-					set this TRUE */
 	/*------------------------------*/
 	ulint		n_mysql_tables_in_use; /* number of Innobase tables
 					used in the processing of the current