Upgrade rust/crates/protobuf to 2.22.0

Test: make
Change-Id: I0967df149e3d7ca88f0abe6281adf2425adc6f1e
diff --git a/build.rs b/build.rs
index b0b1010..653ba35 100644
--- a/build.rs
+++ b/build.rs
@@ -1,7 +1,9 @@
 use std::env;
 use std::fs::File;
-use std::io::{Read, Write};
-use std::path::{Path, PathBuf};
+use std::io::Read;
+use std::io::Write;
+use std::path::Path;
+use std::path::PathBuf;
 use std::process;
 
 // % rustc +stable --version