microdroid: pass idsig in payload.img

apkdmverity is added to microdroid as well.

Bug: 190343842
Test: MicrodroidHostTestCases (not changed)
Change-Id: If5d6608b52cc93cd13ace85c03b5b2891041b8b4
diff --git a/apkdmverity/src/main.rs b/apkdmverity/src/main.rs
index 5094c50..54d5def 100644
--- a/apkdmverity/src/main.rs
+++ b/apkdmverity/src/main.rs
@@ -37,7 +37,7 @@
 use std::path::{Path, PathBuf};
 
 fn main() -> Result<()> {
-    let matches = App::new("apkverity")
+    let matches = App::new("apkdmverity")
         .about("Creates a dm-verity block device out of APK signed with APK signature scheme V4.")
         .arg(
             Arg::with_name("apk")