Fix missing argument in requestedInitialize signal for bitcoin-qt

Summary:
This fixes the `GUI: QObject::connect: No such signal
BitcoinApplication::requestedInitialize(Config *,
HTTPRPCRequestProcessor *)` error encountered on some Linux configs that
caused the software to hang on splash screen with no debug.log.

Test Plan:

./src/qt/test/test_bitcoin-qt
bitcoin-qt

Reviewers: jasonbcox, schancel, #bitcoin_abc, deadalnix

Reviewed By: jasonbcox, #bitcoin_abc, deadalnix

Subscribers: teamcity

Differential Revision: https://reviews.bitcoinabc.org/D2032