Revert "del_auth_mac() returns a list."
Revert "del_auth_mac() returns a list."

This reverts commit 08a136f66f8a7543e7915851e5b73c2fe7814742.

REANNZ/faucet,trungdtbk/faucet,trentindav/faucet,mwutzke/faucet,shivarammysore/faucet,faucetsdn/faucet,gizmoguy/faucet,shivarammysore/faucet,trentindav/faucet,faucetsdn/faucet,trungdtbk/faucet,REANNZ/faucet,mwutzke/faucet,anarkiwi/faucet,anarkiwi/faucet,gizmoguy/faucet