Revert "dist: introduce SCYLLA_IO"
Revert "dist: introduce SCYLLA_IO"

This reverts commit 5cae2560a3edfd75ffab76613e449038b32e019d.

Conflicts:
	dist/common/sysconfig/scylla-server

duarten/scylla,scylladb/scylla,raphaelsc/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,avikivity/scylla,raphaelsc/scylla,duarten/scylla,kjniemi/scylla,kjniemi/scylla,kjniemi/scylla,scylladb/scylla,raphaelsc/scylla,scylladb/scylla