Expose API to restore database from backups

[benoitc]

the backup module can backup and has restore options, but how do we backup?

[iSynaptic]

Can you provide more detail? What are you trying to do?

[rohitjoshi]

How do I restore from an existing backup directory? I don't see pub unsafe extern "C" fn rocksdb_backup_engine_restore_db_from_latest_backup() is made available in the Rust interface.

[iSynaptic]

I can see that the library doesn't expose the ability to restore an backup. Looks like the work has been started but not finished. I've labeled this as a bug. Anyone is free to take on fixing this, otherwise I will plan on it once other in-flight work is completed.

[rohitjoshi]

I have implemented this on my local branch. I will submit a PR.

[iSynaptic]

Looks like this will be addressed in #249 by @rohitjoshi.

[rohitjoshi]

@iSynaptic I am close #249 and splitting into two different PRs.
Submitted #272 for this issue.

[iSynaptic]

Fixed by #272.