Fix two memory safety issues.#1

Merged

AltSysrq merged 2 commits intoAltSysrq:masterfrom

cstorey:master

Sep 14, 2016

Commits on Sep 14, 2016

Ensure that the database name lives for the duration of mdb_dbi_open, avoiding use after free.
Ceri Storey
committed
Ensure we always zero out the TxHandle, even when the call to mdb_txn_commit fails.
Ceri Storey
committed