Make NOT_FOUND errors silent for VPN profiles and keys.

There are several errors printed in keystore2 startup due to above
NOT_FOUND errors.

Test: check keystore2 startup logs.
Change-Id: Icdf553b141cda09f371f7eb83b273444130fe3e7
diff --git a/keystore2/src/error.rs b/keystore2/src/error.rs
index 465dcfa..d1b2ffb 100644
--- a/keystore2/src/error.rs
+++ b/keystore2/src/error.rs
@@ -140,7 +140,7 @@
 /// This function should be used by Keystore service calls to translate error conditions
 /// into service specific exceptions.
 ///
-/// All error conditions get logged by this function.
+/// All error conditions get logged by this function, except for KEY_NOT_FOUND error.
 ///
 /// All `Error::Rc(x)` and `Error::Km(x)` variants get mapped onto a service specific error
 /// code of x. This is possible because KeyMint `ErrorCode` errors are always negative and
@@ -174,7 +174,13 @@
     map_err_with(
         result,
         |e| {
-            log::error!("{:?}", e);
+            // Make the key not found errors silent.
+            if !matches!(
+                e.root_cause().downcast_ref::<Error>(),
+                Some(Error::Rc(ResponseCode::KEY_NOT_FOUND))
+            ) {
+                log::error!("{:?}", e);
+            }
             e
         },
         handle_ok,