Fix a trivial leak in the utility.
clang lint:
* log.c: The left operand of '<' is a garbage value.
* txn_ckpt.c: Branch condition evaluates to a garbage value.
* txn_ckpt.c: Value stored to 'dhandle' is never read.
* log.c: Value stored to 'locked' is never read.
Coverity detected a copy-paste error.