refactor(lock): Pull out path for reuse

Author: epage

src/cargo/ops/lockfile.rs

@@ -53,11 +53,12 @@ pub fn write_pkg_lockfile(ws: &Workspace<'_>, resolve: &mut Resolve) -> CargoRes
     }
 
     if let Some(locked_flag) = ws.gctx().locked_flag() {
+        let lockfile_path = lock_root.as_path_unlocked().join(LOCKFILE_NAME);
         anyhow::bail!(
             "the lock file {} needs to be updated but {} was passed to prevent this\n\
              help: to generate the lock file without accessing the network, \
              remove the {} flag and use --offline instead.",
-            lock_root.as_path_unlocked().join(LOCKFILE_NAME).display(),
+            lockfile_path.display(),
             locked_flag,
             locked_flag
         );