Add/use watchdog with standard timeout

Almost all uses of the watchdog use the same 500ms timeout, so add a new
method that assumes that.

Test: CtsKeystoreTestCases
Change-Id: Idf7852400a58ba954e4a71e5e2282734a0960072
diff --git a/keystore2/src/metrics.rs b/keystore2/src/metrics.rs
index cd1cd75..c114c8b 100644
--- a/keystore2/src/metrics.rs
+++ b/keystore2/src/metrics.rs
@@ -51,7 +51,7 @@
 
 impl IKeystoreMetrics for Metrics {
     fn pullMetrics(&self, atom_id: AtomID) -> BinderResult<Vec<KeystoreAtom>> {
-        let _wp = wd::watch_millis("IKeystoreMetrics::pullMetrics", 500);
+        let _wp = wd::watch("IKeystoreMetrics::pullMetrics");
         map_or_log_err(self.pull_metrics(atom_id), Ok)
     }
 }