Add logging around export of IRemotelyProvisionedKeyPool

If we cannot create an IRemotelyProvisionedKeyPool binder, keystore
starts up as normal. However, we were not logging _why_ the operation
failed. This change adds a bit of logging so that we can diagnose when
devices are missing the IRemotelyProvisionedKeyPool service.

Test: keystore2_test
Change-Id: I60a481dc9762d8b156c5bec9e622a7e2192d145d
diff --git a/keystore2/src/keystore2_main.rs b/keystore2/src/keystore2_main.rs
index bea5f08..d01bfdd 100644
--- a/keystore2/src/keystore2_main.rs
+++ b/keystore2/src/keystore2_main.rs
@@ -152,17 +152,20 @@
     // Even if the IRemotelyProvisionedComponent HAL is implemented, it doesn't mean that the keys
     // may be fetched via the key pool. The HAL must be a new version that exports a unique id. If
     // none of the HALs support this, then the key pool service is not published.
-    if let Ok(key_pool_service) = RemotelyProvisionedKeyPoolService::new_native_binder() {
-        binder::add_service(
-            REMOTELY_PROVISIONED_KEY_POOL_SERVICE_NAME,
-            key_pool_service.as_binder(),
-        )
-        .unwrap_or_else(|e| {
-            panic!(
-                "Failed to register service {} because of {:?}.",
-                REMOTELY_PROVISIONED_KEY_POOL_SERVICE_NAME, e
-            );
-        });
+    match RemotelyProvisionedKeyPoolService::new_native_binder() {
+        Ok(key_pool_service) => {
+            binder::add_service(
+                REMOTELY_PROVISIONED_KEY_POOL_SERVICE_NAME,
+                key_pool_service.as_binder(),
+            )
+            .unwrap_or_else(|e| {
+                panic!(
+                    "Failed to register service {} because of {:?}.",
+                    REMOTELY_PROVISIONED_KEY_POOL_SERVICE_NAME, e
+                );
+            });
+        }
+        Err(e) => log::info!("Not publishing IRemotelyProvisionedKeyPool service: {:?}", e),
     }
 
     binder::add_service(LEGACY_KEYSTORE_SERVICE_NAME, legacykeystore.as_binder()).unwrap_or_else(