Tweak view merging a little

The commit history looks better but now has too many merge commits :-)

In the case where there has been no change to the head
```
ommit c4eb15a09813f50737baf5365d7afb75af2ae4cb
Merge: cbf1025 0ba9a37
Author: 448 <irminsule@openmirage.org>
Date:   Thu Jan 1 01:11:18 1970 +0000

    Merge view to /

commit cbf1025dd42007e68db78f05ad788810418c1e2e
Author: 448 <irminsule@openmirage.org>
Date:   Thu Jan 1 01:11:17 1970 +0000

    Domain 0: merging rm /bench/local/domain/1

commit 0ba9a371649e93ce850cd1e8ce2ba65518fa1acc
Merge: 4a5578e e5e39ae
Author: 448 <irminsule@openmirage.org>
Date:   Thu Jan 1 01:11:16 1970 +0000

    Merge view to /
```
where the parent of cbf102 is 0ba9a37 so c4eb15 is merging a parent into its child.

Is there any way to get rid of the merge commit for this case, but keep it in the general case?