Upgrade rust/crates/protobuf to 2.17.0

* Android.bp was regenerated. New rustc warnings were found.
* Keep local change in src/lib.rs to include out/version.rs.
* Update out/version.rs to the new version.

Change-Id: I9c2f7d412dcd42fe3769505629e05ab949300fe6
Test: make
diff --git a/src/json/json_name.rs b/src/json/json_name.rs
new file mode 100644
index 0000000..f5c9364
--- /dev/null
+++ b/src/json/json_name.rs
@@ -0,0 +1,19 @@
+/// Implementation must match exactly
+/// `ToJsonName()` function in C++ `descriptor.cc`.
+pub fn json_name(input: &str) -> String {
+    let mut capitalize_next = false;
+    let mut result = String::with_capacity(input.len());
+
+    for c in input.chars() {
+        if c == '_' {
+            capitalize_next = true;
+        } else if capitalize_next {
+            result.extend(c.to_uppercase());
+            capitalize_next = false;
+        } else {
+            result.push(c);
+        }
+    }
+
+    result
+}
diff --git a/src/json/mod.rs b/src/json/mod.rs
new file mode 100644
index 0000000..2755aad
--- /dev/null
+++ b/src/json/mod.rs
@@ -0,0 +1,8 @@
+//! JSON serialization and deserialization.
+//!
+//! (Implemented in master, but not ported to stable branch yet).
+
+mod json_name;
+
+#[doc(hidden)]
+pub use self::json_name::json_name;