InnoDB: Handle temporary file creation failure more gracefully.

innobase/row/row0ins.c:
  Don't assert on temp file creation failure.

innobase/row/row0ins.c

@@ -591,8 +591,7 @@ row_ins_set_detailed(
 		
 	FILE*	tf = os_file_create_tmpfile();
 
-	ut_a(tf);
-		
+	if (tf) {
 		ut_print_name(tf, trx, foreign->foreign_table_name);
 		dict_print_info_on_foreign_key_in_create_format(tf, trx,
 			foreign, FALSE);
@@ -600,6 +599,9 @@ row_ins_set_detailed(
 		trx_set_detailed_error_from_file(trx, tf);
 
 		fclose(tf);
+	} else {
+		trx_set_detailed_error(trx, "temp file creation failed");
+	}
 }
 
 /*************************************************************************