Motivation for this change

https://github.com/newsboat/newsboat/blob/master/CHANGELOG.md#2141---2019-02-10

The package fails to build with

    Updating registry `https://github.com/rust-lang/crates.io-index`
error: failed to sync

Caused by:
  failed to load pkg lockfile

Caused by:
  no matching version `= 2.14.0` found for package `libnewsboat` (required by `libnewsboat-ffi`)
location searched: file:///build/newsboat-2.14.1/rust/libnewsboat
versions found: 2.14.1

That's why I added a patch that corrects the versions in Cargo.lock. However, that doesn't seem to be picked up. Can someone experienced with the Rust infrastructure help out?
For reference: https://groups.google.com/d/msg/newsboat/V64yNbmz5U0/QVzHKpVZAwAJ

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.