[BUG] git stash --keep-index undeletes file

[Christian Vetter <christian@xxxxxxxxxxxxxxxxxxx>]

Steps to reproduce
+ mkdir git-stash-test
+ cd git-stash-test
+ git init
+ touch file
+ git add file
+ git commit -m init
+ git rm file
+ git stash push --keep-index
 
 
Result: 
`git status` gives this output:
> On branch master
> Changes to be committed:
>   (use "git reset HEAD <file>..." to unstage)
> 
>         deleted:    file
> 
> Untracked files:
>   (use "git add <file>..." to include in what will be committed)
> 
>         file
 
 
Expected: 
`git status` gives this output:
> On branch master
> Changes to be committed:
>   (use "git reset HEAD <file>..." to unstage)
> 
>         deleted:    file
 
 
Verified on:
+ Windows 10, git version 2.21.0.windows.1 
+ Ubuntu 14.04, git version 2.21.0