Fix tests run with make check when using alternative allocators.

The call to free in line 584 of sharedbook.c mismatches
the _ogg_calloc call used to allocated that data in line 216.

This causes make check to fail when alternative allocators
are used, e.g. the xmm_malloc family of allocators used with
the Lancer optimizations.

Signed-off-by: Ralph Giles <giles@thaumas.net>
2 jobs for master in 1 minute and 42 seconds
Status Name Job ID Coverage
  Build
passed autoconf #11432
docker

00:01:42

passed cmake #11433
docker

00:00:35