cmd/upspin: delete erroneous reference to upspin-foo
cmd/upspin: delete erroneous reference to upspin-foo

It's my test program. Delete the mention for now, but I will
file an issue about how to deal with the combined issue of
showing people their own space while publishing only the
real ones.

Change-Id: Ic1114ba86633e18f5124e76e43c98046f3ce3684
Reviewed-on: https://upspin-review.googlesource.com/8110
Reviewed-by: Eduardo Pinheiro <c9d6fd76b920b269b838bbb70f683c6db503d8d1@gmail.com>

upspin/upspin,upspin/upspin