MDEV-5029 Crash in MariaDB 5.5.33 with .frm from older MariaDB release

Don't fail when an frm is inconsistent (legacy DB_TYPE_xxx code doesn't match the
engine name), use the engine name, ignore the legacy code.

mysql-test/r/bad_frm_crash_5029.result

 show create table t1;
 ERROR 42000: Unknown storage engine 'InnoDB'
+call mtr.add_suppression("t1.frm is inconsistent: engine typecode 43, engine name Aria");
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) DEFAULT NULL,
+  `b` int(11) DEFAULT NULL,
+  `c` int(11) DEFAULT NULL,
+  KEY `a` (`a`),
+  KEY `b` (`b`)
+) ENGINE=Aria DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1
+drop table t1;

mysql-test/t/bad_frm_crash_5029.test

@@ -4,8 +4,17 @@
 # a.k.a. fail to open an frm with indexes:
 
 let $datadir=`select @@datadir`;
-copy_file std_data/mdev5029.frm $datadir/test/t1.frm;
+
+# normal innodb table (but innodb is disabled here)
+copy_file std_data/mdev5029_1.frm $datadir/test/t1.frm;
 --error ER_UNKNOWN_STORAGE_ENGINE
 show create table t1;
 remove_file $datadir/test/t1.frm;
 
+# Aria table, incorrect typecode
+call mtr.add_suppression("t1.frm is inconsistent: engine typecode 43, engine name Aria");
+copy_file std_data/mdev5029_2.frm $datadir/test/t1.frm;
+copy_file std_data/mdev5029_2.MAI $datadir/test/t1.MAI;
+copy_file std_data/mdev5029_2.MAD $datadir/test/t1.MAD;
+show create table t1;
+drop table t1;

sql/table.cc

@@ -1093,7 +1093,10 @@ static int open_binary_frm(THD *thd, TABLE_SHARE *share, uchar *head,
                 plugin_data(tmp_plugin, handlerton *)))
         {
           /* bad file, legacy_db_type did not match the name */
-          goto err;
+          sql_print_warning("%s.frm is inconsistent: engine typecode %d, engine name %s (%d)",
+                        share->normalized_path.str, legacy_db_type,
+                        plugin_name(tmp_plugin)->str,
+                        ha_legacy_type(plugin_data(tmp_plugin, handlerton *)));
         }
         /*
           tmp_plugin is locked with a local lock.