Drop sshpass from our feed as it was upstreamed
Fixes turris/turris-os-packages#547
And easier was to cherry-pick sshpass to OpenWrt 19.07 branch as well instead of doing another merge request in turris-build repository.
Fixes turris/turris-os-packages#547
And easier was to cherry-pick sshpass to OpenWrt 19.07 branch as well instead of doing another merge request in turris-build repository.