init: Remove echo special case from legacy init scripts

The standalone echo command works fine too.

init/src/scheduler.rs

@@ -120,7 +120,6 @@ fn run_command(cmd: Command, config: &mut InitConfig) {
     match cmd {
         Command::RequiresWeak(_) => {} // handled by unit parsing code
         Command::Nothing => {}
-        Command::Echo(text) => println!("{text}"),
         Command::Service(service) => {
             if config.skip_cmd.contains(&service.cmd) {
                 eprintln!(

init/src/script.rs

@@ -45,7 +45,6 @@ pub enum Command {
     Service(Service),
 
     // Misc
-    Echo(String),
     Nothing,
 }
 
@@ -57,7 +56,6 @@ impl Command {
 
         match cmd.as_str() {
             "requires_weak" => Ok(Command::RequiresWeak(args.map(UnitId).collect::<Vec<_>>())),
-            "echo" => Ok(Command::Echo(args.collect::<Vec<_>>().join(" "))),
             "nowait" => {
                 let process = Process::parse(args)?;