calcconfirmsneeded repetitive

[joshuahannan]

The function calcConfirmsNeeded exists both in WalletMainLib and in WalletAdminLib, with the subtle difference of it being public in the first case and private in the second. Since the function simply performs a subtraction between its two parameters, its reason to exist is questionable. Consider (a) removing the function from WalletAdminLib and making the one in WalletMainLib private, or (b) removing the function from both places and using inlined subtractions instead.