vim-patch: Replace shell variables in printf with formatted args

This ensures that special characters in the variables are not
interpreted as escapes/format characters in the printf string, as was
seen with upstream patch 8.0.0615.

    $ ./scripts/vim-patch.sh -p 8.0.0615
    Updating Vim sources: /$HOME/src/neovim/.vim-src
    ✔ Updated Vim sources.
    ✔ Found Vim revision 'bf15b8d78b22661db8b19d662b62bb9a061cdd37'.
    Creating patch...
    Pre-processing patch...
    ✔ Saved patch to '/$HOME/src/neovim/vim-8.0.0615.patch'.

    Fetching 'origin/master'.
    ✔ From https://github.com/neovim/neovim
     * branch                master     -> FETCH_HEAD

    Creating new branch 'vim-8.0.0615' based on 'origin/master'.
    ✔ Switched to a new branch 'vim-8.0.0615'
    Branch 'vim-8.0.0615' set up to track remote branch 'master' from 'origin'.

    Creating empty commit with correct commit message.
    ./scripts/vim-patch.sh: line 40: printf: `w': invalid format character
    ✔ [vim-8.0.0615 db7fbb016] vim-patch:8.0.0615: using ./scripts/vim-patch.sh: line 44: printf: `w': invalid format character
    ✘ [vim-8.0.0615 db7fbb016] vim-patch:8.0.0615: using

[ci-skip]

0 files changed, 0 insertions, 0 deletions