[PATCH 1/2] vi: avoid spurious error if no filename is provided

[Ron Yorston]

Laszlo Papp wrote:
>Do you know under which circumstances it happens? Is this a regression or
>does it require some special environment?
>
>(I cannot reproduce it here with v1.20.2)

It's a regression on the master branch.  The commit is dated 2014-04-05.
The problem isn't present in 1.20.2.

Ron