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/descriptorx.rs b/src/descriptorx.rs
index 033aa2a..82baab8 100644
--- a/src/descriptorx.rs
+++ b/src/descriptorx.rs
@@ -1,16 +1,16 @@
 // Should not be a part of public API
 #![doc(hidden)]
 
-use descriptor::DescriptorProto;
-use descriptor::EnumDescriptorProto;
-use descriptor::EnumValueDescriptorProto;
-use descriptor::FieldDescriptorProto;
+use crate::descriptor::DescriptorProto;
+use crate::descriptor::EnumDescriptorProto;
+use crate::descriptor::EnumValueDescriptorProto;
+use crate::descriptor::FieldDescriptorProto;
 /// utilities to work with descriptor
-use descriptor::FileDescriptorProto;
-use descriptor::OneofDescriptorProto;
+use crate::descriptor::FileDescriptorProto;
+use crate::descriptor::OneofDescriptorProto;
 
-use rust;
-use strx;
+use crate::rust;
+use crate::strx;
 
 // Copy-pasted from libsyntax.
 fn ident_start(c: char) -> bool {