This fixes the cmake -DWITH_ASAN test failure that was mentioned
in commit f9cc3918 (merging
MDEV-12253 from 10.1 to 10.2).

fil_parse_write_crypt_data(): If the tablespace is not found,
invoke fil_space_destroy_crypt_data(&crypt_data) to properly
free the created object.

With this, the test encryption.innodb-redo-badkey still reports
"Missing MLOG_FILE_NAME or MLOG_FILE_DELETE before MLOG_CHECKPOINT"
but does not fail. The misleading message should be corrected,
maybe as part of MDEV-12699.