How do I revert an unversioned file?

[Glenn Morris]

I did a merge from branch B to branch A.
A file that was originally in both branches had been removed
from branch A, and modified in B. It should not be re-added to A.
The result of the merge is a contents conflict in A that I cannot resolve:

Contents conflict in path/to/file
bzr revert path/to/file
bzr: ERROR: Path(s) are not versioned: path/to/file

Sigh. I've had a similar state several times before from various other
operations.

I normally give up at this point and use `bzr revert path/to/'.
But there are a bunch of other changes in that directory that I do
not want to revert.

How do I revert an unversioned file?

Thanks.

PS Do you prefer questions like this to be asked here or via
https://answers.launchpad.net/bzr/ ?