Migrate to the librustutils system property bindings.

Bug: 182498247
Test: Build
Change-Id: Ic16033d7f5e302a3cb7e591a0fa2ae403755fc2e
diff --git a/keystore2/src/super_key.rs b/keystore2/src/super_key.rs
index 4b71bb5..a1e4c48 100644
--- a/keystore2/src/super_key.rs
+++ b/keystore2/src/super_key.rs
@@ -46,13 +46,13 @@
     aes_gcm_decrypt, aes_gcm_encrypt, generate_aes256_key, generate_salt, Password, ZVec,
     AES_256_KEY_LENGTH,
 };
+use rustutils::system_properties::PropertyWatcher;
 use std::{
     collections::HashMap,
     sync::Arc,
     sync::{Mutex, Weak},
 };
 use std::{convert::TryFrom, ops::Deref};
-use system_properties::PropertyWatcher;
 
 const MAX_MAX_BOOT_LEVEL: usize = 1_000_000_000;
 /// Allow up to 15 seconds between the user unlocking using a biometric, and the auth