tests: fix thinko in ElectrumTestCase base class
tests: fix thinko in ElectrumTestCase base class

can't see why it was cross-calling the setUpClass from the
individual test setUp

spesmilo/electrum,spesmilo/electrum,wakiyamap/electrum-mona,wakiyamap/electrum-mona,spesmilo/electrum,wakiyamap/electrum-mona,pooler/electrum-ltc,pooler/electrum-ltc,spesmilo/electrum,pooler/electrum-ltc,pooler/electrum-ltc,wakiyamap/electrum-mona