gnu: Remove rust-nb-1.

* gnu/packages/crates-io.scm (rust-nb-1): Delete variable.

Change-Id: I51ea3e2894ca26daac445649e841dcbafeffa5f5

gnu/packages/crates-io.scm

@@ -38935,24 +38935,6 @@ linear algebra library.")
      "This package provides a crate to perform natural ordering for Rust.")
     (license license:expat)))
 
-(define-public rust-nb-1
-  (package
-    (name "rust-nb")
-    (version "1.0.0")
-    (source
-     (origin
-       (method url-fetch)
-       (uri (crate-uri "nb" version))
-       (file-name (string-append name "-" version ".tar.gz"))
-       (sha256
-        (base32 "1blc9143cqh3cn2imr050qczbnfrfdl10xxnfdggamlybnn3fv2l"))))
-    (build-system cargo-build-system)
-    (arguments `(#:skip-build? #t))
-    (home-page "https://github.com/rust-embedded/nb")
-    (synopsis "Minimal non-blocking I/O layer")
-    (description "This package provides a minimal non-blocking I/O layer.")
-    (license (list license:expat license:asl2.0))))
-
 (define-public rust-nb-connect-1
   (package
     (name "rust-nb-connect")