liquidityprovider broken

[patorsky]

This commit broke -liquidityprovider feature.
Calling PrepareDenominate for each value from nPrivateSendRounds to 0 in loop is too heavy (100% cpu load). With -liquidityprovider feature (nPrivateSendRounds == 99999) we constantly hit timeout.

Log:

2017-12-24 03:31:59 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for 99999 rounds, error: Can't select current denominated inputs
...
2017-12-24 03:32:38 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for 82810 rounds, error: Can't select current denominated inputs
2017-12-24 03:32:38 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for 82809 rounds, error: Can't select current denominated inputs
2017-12-24 03:32:38 CPrivateSendClient::CheckTimeout -- Session timed out (30s) -- restting
2017-12-24 03:32:38 CPrivateSendClient::SetState -- nState: 0, nStateNew: 4
2017-12-24 03:32:38 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for 82808 rounds, error: Can't select current denominated inputs
2017-12-24 03:32:38 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for 82807 rounds, error: Incorrect session denom
2017-12-24 03:32:38 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for 82806 rounds, error: Incorrect session denom
...
2017-12-24 03:32:40 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for 2 rounds, error: Incorrect session denom
2017-12-24 03:32:40 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for 1 rounds, error: Incorrect session denom
2017-12-24 03:32:40 CPrivateSendClient::SubmitDenominate -- Running PrivateSend denominate for all rounds, error: Incorrect session denom

As a side note: calling SetNull before SetState cause this strange log outputs like nState: 0, nStateNew: 4 or Incorrect session denom.

[nmarley]

Fixed in #1829