tree-wide: Don't explicity disable copy-on-write when copying images

Since the copy helpers now copy file attributes as well, let's not
explicitly disable copy-on-write anymore when we copy an image. If
the source already has copy-on-write disabled, the copy will have it
disabled as well. Otherwise, the copy will also have copy-on-write
enabled.

This makes sure that reflinks always work as reflink is only supported
if both source and target are copy-on-write or both source and target
are not copy-on-write.

src/nspawn/nspawn.c

@@ -6072,10 +6072,8 @@ static int run(int argc, char *argv[]) {
 
                         {
                                 BLOCK_SIGNALS(SIGINT);
-                                r = copy_file_full(arg_image, np, O_EXCL, arg_read_only ? 0400 : 0600,
-                                                   FS_NOCOW_FL, FS_NOCOW_FL,
-                                                   COPY_REFLINK|COPY_CRTIME|COPY_SIGINT,
-                                                   NULL, NULL);
+                                r = copy_file(arg_image, np, O_EXCL, arg_read_only ? 0400 : 0600,
+                                              COPY_REFLINK|COPY_CRTIME|COPY_SIGINT);
                         }
                         if (r == -EINTR) {
                                 log_error_errno(r, "Interrupted while copying image file to %s, removed again.", np);