Get rid of --disable-locks (aka transactional memory) configure option

[ifranzki]

The use of transactional memory is broken in openCryptoki anyway. Also, many code paces use locks, even with --disable-locks. --enable-locks is the default anyway.

This would also allow us to remove some source files that are duplicates from the with-locks version:

• lock_btree.c vs. btree.c
• lock_sess_mgr.c vs. sess_mgr.c

Some source files have #ifdef ENABLE_LOCKS to distinguish the 2 cases:

• local_types.h
• hostdefs.h
• apiutil.c