Drop orphan InnoDB table (aka. #sql-ib123)

Crash during ALTER TABLE and using innodb_file_per_table=1 might leave a orphan table in the filesystem. Giving the ALTER TABLE another go gives you strawberries:

ERROR 1050 (42S01): Table 'blogblerp/#sql-ib639' already exists

In order to drop the table name needs to be escaped with #mysql50#

MariaDB [(none)]> use blogblerp;
MariaDB [(blogblerp)]> drop table `#mysql50##sql-ib639`;
Query OK, 0 rows affected (0.01 sec)