app-crypt/nitrocli: Add patch for build failure with Rust 1.35

app-crypt/nitrocli: Add patch for build failure with Rust 1.35

With dev-lang/rust-1.35 (or higher, presumably) nitrocli fails to build
because of a unused comments that are flagged starting with this
version.
The change has been fixed upstream and with this change we add a patch
back porting the fix to 0.2.3.

Closes: https://bugs.gentoo.org/686870
Signed-off-by: Daniel Müller <deso@posteo.net>
Closes: https://github.com/gentoo/gentoo/pull/12119
Signed-off-by: Georgy Yakovlev <gyakovlev@gentoo.org>