Restrict protobuf version to 2.10 with patches

Cargo.toml

 system-libz = ["flate2"]
 
 [dependencies]
-protobuf = "2.0"
+protobuf = "~2.10"
 byteorder = "1.1"
 flate2 = { version = "1.0", optional = true }
 inflate = "0.4"