fix(cpu-template-helper): Don't show error message twice

The CPU template helper tool showed its error message twice as follows:
```
$cpu-template-helper fingerprint compare --prev A.json --curr B.json
Difference detected between source and target:\\n{
  "name": "kernel_version",
  "prev": "5.10.215-203.850.amzn2.x86_64",
  "curr": "6.1.84-99.169.amzn2023.x86_64"
}
Error: FingerprintCompare(DiffDetected("{\n  \"name\": \"kernel_..."))
```

It is because it returned `Result` from `main()` to return an exit code
and it shows its error message on error. Instead just return the exit
code using `std::process::exit()`.

Signed-off-by: Takahiro Itazuri <[email protected]>

Author: zulinx86

src/cpu-template-helper/src/main.rs

@@ -190,14 +190,14 @@ fn run(cli: Cli) -> Result<(), HelperError> {
     Ok(())
 }
 
-fn main() -> Result<(), HelperError> {
+fn main() {
     let cli = Cli::parse();
     let result = run(cli);
     if let Err(e) = result {
         eprintln!("{}", e);
-        Err(e)
+        std::process::exit(1);
     } else {
-        Ok(())
+        std::process::exit(0);
     }
 }