tdb: update tdb ABI to use hide_symbols=True

tdb: update tdb ABI to use hide_symbols=True

We now use -fvisibilty=hidden to hide symbols from outside the tdb
shared library.

This also moved tdb_transaction_recover() into the tdb_private.h
header, as it should never have been a public API. For that reason we
are changing the version number. We're only doing a minor version
increment as it is extremely unlikely that anyone was actually using
tdb_transaction_recover() as its locking requirements were rather
unusual.

Pair-Programmed-With: Rusty Russell <rusty@samba.org>

(Imported from commit 773a8afbba27a5e2e48577100f3ca9873b506615)