Dockerfile: don't suppress error message (#4509)
Dockerfile: don't suppress error message (#4509)

The `-qq` flag will suppress helpful output in case
of an error.
neocogent/electrum,wakiyamap/electrum-mona,spesmilo/electrum,pooler/electrum-ltc,fujicoin/electrum-fjc,cryptapus/electrum,wakiyamap/electrum-mona,neocogent/electrum,wakiyamap/electrum-mona,vialectrum/vialectrum,fujicoin/electrum-fjc,asfin/electrum,cryptapus/electrum,wakiyamap/electrum-mona,spesmilo/electrum,cryptapus/electrum,vialectrum/vialectrum,pooler/electrum-ltc,spesmilo/electrum,pooler/electrum-ltc,neocogent/electrum,vialectrum/vialectrum,spesmilo/electrum,pooler/electrum-ltc,fujicoin/electrum-fjc,asfin/electrum,asfin/electrum