Correctness failure with "Attempting to change status of a different index build"

[apkar]

Occasional failures not reproducible with any specific seed, but reproduce in 1 out of 4000 runs.

[apkar]

If a transaction is failed while updating the index status, failure handler (catch block) would try to update the status to error. But, it is possible transaction has failed even before index status was set causing the buildId to mismatch. This needs to be fixed properly with transaction management. Delaying that until #68. #121 just makes this error more explicit and tries to make the contract more obvious.