ncp-spinel: Join: Allow `ALREADY` error when setting `PROP_NET_IF_UP`
ncp-spinel: Join: Allow `ALREADY` error when setting `PROP_NET_IF_UP`

d-bahr/wpantund,openthread/wpantund,aeliot/wpantund,openthread/wpantund,d-bahr/wpantund,openthread/wpantund,abtink/wpantund,aeliot/wpantund,d-bahr/wpantund,abtink/wpantund,d-bahr/wpantund,abtink/wpantund,aeliot/wpantund,abtink/wpantund,openthread/wpantund,aeliot/wpantund