Restore --gen argument for binaries (#1805)

#1799 renamed `gen` → `generation`, because the former is a reserved
word in Rust 2024. That PR special-cased the `generation` field in the
volume construction request, because it's serialized to disk; however,
we should also special-case CLI arguments to avoid breaking existing
scripts.

Author: mkeeter

crudd/src/main.rs

@@ -40,7 +40,7 @@ pub struct Opt {
     key: Option<String>,
 
     /// Generation
-    #[clap(short, long, default_value = "0", action)]
+    #[clap(short, long = "gen", default_value = "0", action)]
     generation: u64,
 
     /// TLS certificate

crutest/src/main.rs

@@ -174,7 +174,7 @@ pub struct Opt {
     #[clap(long, global = true, action)]
     flush_timeout: Option<f32>,
 
-    #[clap(short, global = true, long, default_value_t = 0, action)]
+    #[clap(short, global = true, long = "gen", default_value_t = 0, action)]
     generation: u64,
 
     /// The key for an encrypted downstairs.

hammer/src/main.rs

@@ -37,7 +37,7 @@ pub struct Opt {
     #[clap(short, long, action)]
     key: Option<String>,
 
-    #[clap(short, long, default_value = "1", action)]
+    #[clap(short, long = "gen", default_value = "1", action)]
     generation: u64,
 
     /*

measure_iops/src/main.rs

@@ -21,7 +21,7 @@ pub struct Opt {
     #[clap(short, long, action)]
     key: Option<String>,
 
-    #[clap(short, long, default_value = "0", action)]
+    #[clap(short, long = "gen", default_value = "0", action)]
     generation: u64,
 
     #[clap(long, action)]

nbd_server/src/main.rs

@@ -37,7 +37,7 @@ pub struct Opt {
     #[clap(short, long, action)]
     key: Option<String>,
 
-    #[clap(short, long, default_value = "0", action)]
+    #[clap(short, long = "gen", default_value = "0", action)]
     generation: u64,
 
     // TLS options