tindex: Amend last commit a bit.

When you run `git log foo` foo can be, from git-log(1),
`[<revision range>] [[--] <path>...]`, so, may things.

- A "revision range" described by gitrevision(7) (don't got there unless
  you have a few hours, or already lost your sanity), which can be :
  * a commit hash,
  * a tag
  * a branch,
  * a ref name
  * a "describe output"
  * and many other ways to describe revisions
  * a range made by any of the above
- An existing path.

When it can't find any of those, git figures out that you meant
something else and made a typo, and exits.

If you really meant a path, you have to run `git log -- foo`. Then git
knows that you meant a path and only a path, it will then assume that
you knew what you meant, and will go look in the history.

Tools/scripts/tindex

@@ -42,11 +42,9 @@ fi
 # --------------------------------------------------------
 
 blame() {
-  # Find out who is responsible for current version of file $1, if not deleted
+  # Find out who is responsible for current version of file $1
 
-  if [ -e $1 ]; then
-    ${GIT} log --no-patch --max-count=1 --format='%ce' $1
-  fi
+  ${GIT} log --no-patch --max-count=1 --format='%ce' -- $1
 }
 
 indexfail() {