Fix ethash git submodule to prevent bad access for anyone is not in LedgerHQ. [skip ci]
Fix ethash git submodule to prevent bad access for anyone is not in LedgerHQ. [skip ci]

LedgerHQ/lib-ledger-core,LedgerHQ/lib-ledger-core,LedgerHQ/lib-ledger-core,LedgerHQ/lib-ledger-core,LedgerHQ/lib-ledger-core,LedgerHQ/lib-ledger-core,LedgerHQ/lib-ledger-core