reset member committed and rolledBack when start transaction sucessfully in AdoTransaction.Begin.

I have reviewed AdoTransaction.cs . and I found, It is better that reset committed and rolledBack to false after start transaction successfully.
Because if we start a transaction and commit, then, we call session.BeginTransaction to start another transaction, but at this time, session.Transaciton.WasCommitted returns true.

So reset commited and rolledBack after successful to start transaction is necessary.
eg:

public void Begin()
{
log.Debug( "begin" );

try
{
IsolationLevel isolation = session.Factory.Isolation;
if( isolation == IsolationLevel.Unspecified )
{
trans = session.Connection.BeginTransaction();
}
else
{
trans = session.Connection.BeginTransaction( isolation );
}

committed = false;
rolledBack = false;
}
catch( Exception e )
{
log.Error( "Begin transaction failed", e );
throw new TransactionException( "Begin failed with SQL exception", e );
}

begun = true;
}