Don't double-free an UnparsedSource

github.com/containers/image.FromUnparsedImage() "takes ownership" of the
UnparsedImage that we pass to it, so we shouldn't also Close() the
UnparsedImage ourselves after we've wrapped it up in an Image object.

Since creating an Image is the only thing we do with the UnparsedImage
after creating it from a SourceImage, just use the FromSource() function
to handle both steps at once.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

pkg/storage/image.go

@@ -137,10 +137,9 @@ func (svc *imageService) CanPull(imageName string, options *copy.Options) (bool,
 	if err != nil {
 		return false, err
 	}
-	unparsedImage := image.UnparsedFromSource(rawSource)
-	defer unparsedImage.Close()
-	src, err := image.FromUnparsedImage(unparsedImage)
+	src, err := image.FromSource(rawSource)
 	if err != nil {
+		rawSource.Close()
 		return false, err
 	}
 	src.Close()