exit failsafe_reader if incorrect args are supplied

src/failsafe_reader.rs

@@ -11,6 +11,7 @@ fn main() -> diag_device::DiagResult<()> {
     let args: Vec<String> = std::env::args().collect();
     if args.len() != 2 {
         println!("Usage: {} /path/to/failsafe/file", args[0]);
+        std::process::exit(1);
     }
     let mut failsafe_reader = FailsafeFileReader::new(&args[1])?;