Remove redundant Ord implementation for Version.

I've forgot why we keep them, so let me know if you know their reason
for existing.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Fix unused import warnings.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Remove an unused variable in a test of std::c_str.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
Remove unnecessary parentheses.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
rustpkg has gone.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
auto merge of #12109 : omasanori/rust/small-fixes, r=sfackler

Most of them are to reduce warnings in testing builds.