Modified the condition for skipping innodb.innodb-autoinc to exclude

the part which was defined by MariaDB version and thus caused a wrong
check result

mysql-test/suite/innodb/t/innodb-autoinc.test

-if (`select plugin_auth_version <= "5.5.37-MariaDB-34.0" from information_schema.plugins where plugin_name='innodb'`)
+if (`select plugin_description like '%XtraDB%' and substr(plugin_auth_version,16) <= "34.2" from information_schema.plugins where plugin_name='innodb'`)
 {
-  --skip Not fixed in XtraDB as of 5.5.37-MariaDB-34.0 or earlier
+  --skip Not fixed in XtraDB as of 34.2 or earlier
 }
 
 --source include/have_innodb.inc