* Withdraw authority no longer implies a custodian
Before this change, if the withdraw authority and custodian had
the same public key, then a withdraw authority signature would
imply a custodian signature and lockup would be not be enforced.
After this change, the client's withdraw instruction must
explictly reference a custodian account in its optional sixth
account argument.
Likewise, the fee-payer no longer implies either a withdraw
authority or custodian.
* Fix test
The test was configuring the stake account with the fee-payer as
the withdraw authority, but then passing in a different key to
the withdraw instruction's withdraw authority parameter. It only
worked because the second transaction was signed by the fee-payer.
e33f9ea6b5