Remove outdated domains [skip ci]

Source/domainset/reject_sukka_extra.conf

@@ -1059,7 +1059,6 @@
 .fcpool.com
 .miningkings.com
 .fixminer.com
-.stringengines.com
 .formulawire.com
 .fortpush.com
 .gigarho.com
@@ -1423,7 +1422,6 @@
 .miningpool.online
 .letshash.online
 .cryptopool.online
-.superpools.online
 .goldencoin.online
 .bitstar-platform.online
 .51pool.online
@@ -1432,7 +1430,6 @@
 .mypool.online
 .miningcrypto.online
 .cryptoluck.online
-.txchange.online
 .dgb256.online
 .mangocoin.online
 .besocial.online