add protobuf3 ppa for sdk docker
add protobuf3 ppa for sdk docker

karlnapf/shogun,shogun-toolbox/shogun,sorig/shogun,sorig/shogun,lambday/shogun,lisitsyn/shogun,besser82/shogun,geektoni/shogun,lambday/shogun,lambday/shogun,besser82/shogun,geektoni/shogun,karlnapf/shogun,lisitsyn/shogun,karlnapf/shogun,geektoni/shogun,lisitsyn/shogun,besser82/shogun,shogun-toolbox/shogun,shogun-toolbox/shogun,lambday/shogun,shogun-toolbox/shogun,lisitsyn/shogun,lambday/shogun,lambday/shogun,sorig/shogun,karlnapf/shogun,sorig/shogun,shogun-toolbox/shogun,geektoni/shogun,besser82/shogun,shogun-toolbox/shogun,geektoni/shogun,lisitsyn/shogun,karlnapf/shogun,besser82/shogun,geektoni/shogun,karlnapf/shogun,besser82/shogun,sorig/shogun,sorig/shogun,lisitsyn/shogun