hostid: return correct exit code on error

src/uu/hostid/src/hostid.rs

@@ -19,7 +19,7 @@ extern "C" {
 
 #[uucore::main]
 pub fn uumain(args: impl uucore::Args) -> UResult<()> {
-    uu_app().get_matches_from(args);
+    uu_app().try_get_matches_from(args)?;
     hostid();
     Ok(())
 }

tests/by-util/test_hostid.rs

@@ -10,3 +10,12 @@ fn test_normal() {
     let re = Regex::new(r"^[0-9a-f]{8}").unwrap();
     new_ucmd!().succeeds().stdout_matches(&re);
 }
+
+#[test]
+fn test_invalid_flag() {
+    new_ucmd!()
+        .arg("--invalid-argument")
+        .fails()
+        .no_stdout()
+        .code_is(1);
+}