* Fix typos
* Return http 400 when wrong unseal key is supplied
* Add changelog
* Add test cases and change one more return case to http 400
The new case is triggered when key length is within valid range
[16, 32], but it has uneven bytes, causing crypto/aes to return
invalid key size.
* remove expected in unit tests
* include error in the new error reason
* add multikey and autoseal test cases
* return invalid key for few more code paths
