Camera NDK: don't explicit delete ACameraMetadata

To fix the warning in RefBase destructor.

Test: NDK CTS tests, and ARCore measure app.
Bug: 112775599
Change-Id: Ia448ac6d7e6c17699c16d287f65fc2826c9d7578
diff --git a/camera/ndk/impl/ACameraDevice.cpp b/camera/ndk/impl/ACameraDevice.cpp
index 907debc..c908323 100644
--- a/camera/ndk/impl/ACameraDevice.cpp
+++ b/camera/ndk/impl/ACameraDevice.cpp
@@ -50,11 +50,11 @@
 CameraDevice::CameraDevice(
         const char* id,
         ACameraDevice_StateCallbacks* cb,
-        std::unique_ptr<ACameraMetadata> chars,
+        sp<ACameraMetadata> chars,
         ACameraDevice* wrapper) :
         mCameraId(id),
         mAppCallbacks(*cb),
-        mChars(std::move(chars)),
+        mChars(chars),
         mServiceCallback(new ServiceCallback(this)),
         mWrapper(wrapper),
         mInError(false),
@@ -436,7 +436,7 @@
     if (req == nullptr) {
         return;
     }
-    delete req->settings;
+    req->settings.clear();
     delete req->targets;
     delete req;
 }